Corrected entry: Sophia decides to move in with her son Phil and his wife, but later decides not to and she feels bad for Phil's wife. But in the episode "Ebbtide's Revenge" we learn that Sophia hates Phil's widow Angela and hasn't been to see him for 20 years.
Correction: Also, there is an episode (the one where Rose dates the short doctor) where she goes to her grandson's graduation from dog grooming school, where she said "the big dope failed." That episode aired before the two mentioned in the original mistake listed, so she saw her son and daughter in law within the last 20 years.
Correction: Sophia doesn't decide to move in with Phil AND his wife. She is going to move in with Phil only because his wife, whom she hates, left Phil. She left two kids behind with Phil because they can't cross state lines, and Sophia is going to help him raise the kids.