In 2019, Alexis Davis was going to start therapy sessions again but she was referred to a Dr. Neil Byrne by Ryan Chamberlain (who was pretending to be Kevin Collins at the time) since it would be a conflict of interest due to her representing Laura Collins in her "divorce" from "Kevin." She got into an argument with her ex-husband Julian Jerome and when he was out of earshot she made a derogatory statement about him and a man sitting next to her at the bar thought she directed that statement towards him. She clarified that that statement was towards her ex-husband Julian, not him. She then said that he seemed to be nothing like Julian and that he was a guy sitting at a bar alone reading a book which kind of insulted him but she quickly fixed her mistake and said that his book looked like a real "page-turner." The title was called "Russian Diaspora of the early 20th century" which made Alexis wonder if he was a professor but the man said that he was a doctor and a history enthusiast. Alexis got a ginger to drink and she vented about her troubles in her life to the man who listened to her and offered his own experiences and told her that she might just need herself for her next breakthrough and not her ex. The man invited Alexis to continue their conversation over dinner and she told him it was not a good idea so he left her his card in case she changed her mind.
Alexis later went to see Dr. Neil Byrne for her therapy appointment and was shocked to see that it was the same man she talked to at Charlie's Pub earlier that evening. He was also surprised and he initially gave her a referral to another therapist in case she was uncomfortable and she left but came back and decided to do therapy sessions with him. She asked if he knew she was going to be his patient and he said he didn't. Neil also explained that if he had known she was his new patient then he would never have asked her to dinner. They then began therapy sessions and she told him about her choices she's made when it comes to men she has been with. She explained to Neil that she was attracted to men who were dangerous, selfish, and incapable of intimacy and told Neil that her father Mikkos Cassadine set that pattern up for her. She explained that she never earned her father's love and that's why she was attracted to dangerous men like him. After their first appointment, Alexis began to see Neil as her therapist on a regular basis.
On April 8, 2019, Alexis ran into Neil at The Floating Rib and she told him that her daughter Kristina was in a cult called "Dawn Of Day." Neil explained that if she pushes Kristina to realize she was in a cult, then Kristina would just go deeper into Dawn Of Day so the key was to plant seeds of doubt in her head to cause her to see Dawn Of Day in a more critical way. Neil was later summoned by Sonny Corinthos who asked for his help in getting Kristina out of Dawn Of Day. Neil told Sonny about a treatment plan called exit therapy and that the last case he worked on meant that there was no guarantee it would work. Sonny pleaded for his help and Neil eventually agreed to do exit therapy with Kristina.
On April 23, Neil began exit therapy with Kristina and her family and the session went sideways when she lashed out at everyone as she was defending Dawn Of Day.
On May 6, Neil began another session and her brother Michael brought his friend Willow Tait over to the safehouse and she told Kristina what Shiloh did to her. She told her that her mother had drugged her, tattooed her and then Shiloh came in and had sex with her. Everyone in the room was horrified and Kristina was in denial about Shiloh doing that to people initiated in the trust but then accepted the fact that he used her. Neil eventually opened the door and told Kristina she has a choice; DOD or her family. Alexis and Sonny were happy that she chose her family.
Although Kristina no longer believed in what Dawn Of Day does, Neil continued to work with her and help her.
On June 3, it was revealed that Neil had a wife and daughter.
On June 11, Alexis had another session with Neil and ended up bringing up his daughter and he ended the session early. Alexis later came back and apologized to Neil for bringing his personal business into their Doctor/Patient relationship. He forgave her, but asked her to respect their boundaries.
On July 3, after Kristina had a session with Neil, Alexis went in and had her's. As they talked about Kristina and as Alexis was wondering what was in the pledge she slipped up and mentioned that Neil knew what it was like losing a child which made him mad. He got even more angry when Alexis revealed she knows he lost his daughter Joanne and he ended the session early. He said he can no longer treat her since she did not respect the boundaries of their professional relationship. He asked her to leave and she tried to apologize to him. He again asked her to leave and she accused him of taking his grief out on her but he said that's not what's happening. He offered to refer her to someone else but she said it wouldn't be necessary and left. As she was leaving Kristina got back and decided to talk about what was in the pledge so Neil invited them both in and Kristina revealed that she lied and said that Alexis deliberately hit her abusive ex-boyfriend Kiefer Bauer when really it was by accident and she was under emotional duress. Kristina asked for forgiveness and Alexis immediately forgave her. After the session, Alexis came back and asked Neil to hear her out and he invited her in and Alexis apologized again for her actions and said she regrets what happened and Neil said he did too. He also said he didn't trust her anymore and Alexis mentioned that she is more comfortable talking to him than anyone else. She teared up and said that she saw him as more than a therapist, she saw him as a friend and she said she really needs a good therapist. She went to leave but Neil stopped her and invited her back for another session on Tuesday at 5 PM and she accepted the invitation.
On July 31, Neil got stuck in an elevator with Alexis and was worked up because the day marks five years since his daughter Joanna died. Neil eventually opened up to Alexis about how she died by revealing that Joanna was in a different cult that was about drugs. She took her own life and was pronounced dead at 9:47 PM. He revealed that every year since then on July 31 that he would go down and sing "Hush Little Baby" on the karaoke, explaining that she loved that song until she joined the drug cult. Alexis encouraged Neil to sing in the elevator and he did.
The next day (shown on August 5), Neil showed up at Alexis' and said that he couldn't see her as a patient anymore. Alexis was dumbfounded and shocked and mentioned she was respecting their boundaries and he acknowledged that she did but he did not. Neil explained that his job was to help his patients and he couldn't take care of Alexis without her figuring out to take care of him and that they wouldn't be able to look at each other the same way again. They admitted that they cared about each other and Alexis eventually accepted that they "crossed the point of no return" and asked if they could get to know each other better.
On September 6, it was revealed that Neil and Alexis went on a date to play a bingo game, hosted by drag queens. When Alexis won, she was given a stuffed animal as a prize and she kissed Neil, who didn't object.
On October 11, Neil began treating Brad Cooper, who was feeling a lot of anxiety and guilt since he switched his dead son he adopted with his husband Lucas Jones with Nelle Benson's son with Michael Corinthos, essentially robbing Michael of his kid. Neil gave Brad a prescription to help with his anxiety and suggested that he bring Lucas next time. On October 28, Lucas and Brad went to see Neil and Lucas felt that Brad was keeping something from him and Brad was upset because of Lucas' suspicions even though Lucas was right.
On October 29, Neil brought food over for Alexis and then was going to stay with her but Alexis began feeling sick so she sent Neil home. Eventually, Alexis was taken to the hospital where she suddenly had rashes on her hands and some her hair began to fall out. Neil and T.J. Ashford were boxing up any cleaning stuff she had to test them in case she was exposed to some kind of poison.
On November 15, T.J. put together that Alexis ingested thallium which is used in rat poisoning. The test was ran which confirmed T.J.'s theory and Alexis began drinking blue paint to get it out of her system.
On November 25, Neil put the pieces together and learned that Julian had spotted Kendra Lennon in the alley behind Charlie's and later on saw the dead rats. He eventually began to suspect Kendra had poisoned her on purpose and shared his suspicions with Alexis.
On November 28, Neil saw that Alexis left the hospital and when he tried to call her and she didn't answer, he was warning her not to approach Kendra. Julian and Neil teamed up to find her and they discovered that Kendra's real name is Kendra Bauer and they eventually got her location. Neil and Julian found Alexis on the side of the road who had been slowly regaining her movement after being temporarily paralyzed. Alexis tried to call someone for Kendra who taunted her one last time before dying. Neil got Alexis back to the hospital to get checked out.
In 2020, Alexis and Neil leave town and have a one night stand. They lie about their relationship to the board and since Britt saw them together in a hotel room, they were suspended. Neil didn’t contact Alexis after she was suspended. They briefly talked and may get back together soon.
After getting back together and spending the night on August 31, Neil is found dead the following morning. Valerie says it was a presumed heart attack after he had sex with Alexis.