If Monica Quartermaine is the grandmother of Michael, then she has to be the mother-in-law of Sonny Cortinthos. Sonny is not only the son-in-law of Monica, he's also added Monica to his mob because they're both Family-Oriented. Alice has to be Sonny's housekeeper when he arrives to Monica's house.
Yes normally in the real-world that might be the case of Monica and Sonny being family-connected. However, Sonny is the adoptive father of Michael Corinthos. Michael's biological parents are Carly Benson-Jaxs-Corinthos and A.J. Quartermaine. Monica is Michael's grandmother through A.J. not Carly. Your thinking would be true if Michael's mother would be one of the Quartermaine's (which Carly is not - she is the daughter of Bobbie Spencer - sister of Luke Spencer and John Durant)
Alice is the Quartermaine's housekeeper, not Sonny's. Sonny is Michael's adoptive father, AJ is the Quartermaine. Sonny has no connections to the Quartermaines besides having Jason being his former bodyguard/enforcer and Michael (as his adoptive son)
O.k. now I watched the 1-24-13 episode. I see how you see Tracy and Sonny, but still don't see the connection between Sonny-Monica/Alice. However, I will wait and see how the storyline unfolds and I might figure it out!