Many times people use guilt as a way to fix their situation. Maybe Mom doesn't want Sonny to be at her house any longer. An easy way to getting him out would be to send him "home" to his wife.
This was true of my father-in-law. He had my AH living with them before I came along. He was so thrilled that AH came to live with me, he did everything he could to keep us together. He was always happy to give my AH money to bail him out of a jam if it meant I wouldn't be so angry and throw him out. Many timeshe convinced my my AH loved me and was trying. When I finally separated and filed for my divorce he even lectured me on the phone about how marriag eis a commitment, etc etc. That all stopped once he realized my ex already had a new girlfriend lined up to take care of him and provide a place to stay.
Now I am sure he is telling her how happy he is his son found her and all my AH needs is the right woman to straighten him out.
Once you realize that all these people are doing what is bets fro themselves, it becomes easier to realize you ought to be focusing on what is best for you.