When is it okay to step back from family?

So, my fiance's mom ....Ive known her for a decade and in all that time, she has always been surfacey nice to me, but never really made me feel welcome. Some of my friends who know her, have always told me they think she is jealous or resentful of me "taking away her baby son." She has babied them SO much, to the point where the oldest is 40 years old and refuses to work, while she brings him 3 meals a day in his bedroom while he plays video games. And she loves it. My fiance has never allowed her to baby him and constantly has to hear how much she hates that he has a job, and hates that he doesnt live at home anymore, etc etc. Its stressful. So, I have always tried really hard to have a relationship with her, invite her to dinner, do things with her etc. Usually when she would come to dinner, she would make a comment about how something had onions in it and the older brother doesnt like onions and could I fix something else for him, etc. Always something like that. Or we would suggest meeting somewhere for dinner, but she wouldnt want to wait until 6 pm to eat, so she and the oldest son would go out without us. She lives in a house that is packed with a hoard, falling down around her, and has no quality of life and I cant go visit over there anymore. She was a daycare worker until she lost her job a few months ago, and she is in the worst health imaginable. She doesnt take care of her teeth and she's been walking around with 6 absesed teeth in her head to the point of not being able to eat properly. She has a shoulder problem that the doctor said he could easily take care of with outpatient surgery, but she wont, so she cant use her arm anymore. The doctor told her 25 years ago that her appendix was completely diseased and needed to be removed asap, but she didn't and somehow it is still there, and now, she has breast cancer which could have easily been treated, but she stopped chemo after the first treatment bc she didnt like how it made her feel. So now she's totally not treating the cancer, and of course it will eventually spread to other places, and be a long, painful way out. I havent been able to talk to her on the phone or see her since October. She was calling me every single day being SO negative, and complaining non stop about all of her health issues, which she has Extremely good health insurance to take care of. I couldnt listen to it anymore. And she would call me to drive across town in the middle of my work day to bring her the newspaper, or peanut butter, when her grown son lives in the house with her. I guess I cant stand her helpless attitude when she could have done everything to help herself and chose not to. So now she calls my fiance, all day long at work, crying and going manic about her health, while he's at work, and several times when he gets home at night. And he's super down about it, but she's his mother, so he just comforts her and listens. Idk what to do, or if Im being a really awful person for stepping back with her? What do you think? I feel like Im trying to save my sanity and energy to help my fiance when this gets really bad. Its already emotionally traumatizing enough for everyone involved and is a major stress factor on our relationship. Am I a bad person to step away from what little relationship I had with her and try and preserve my own sanity in this situation?

/r/AskReddit Thread