I was caretaker of my mom for almost 25 years. Her brother moved back and took over, then left. Now I'm back, mom keeps calling him. Help?

My mom is bipolar. Ive been taking care of her since 15. I've had to commit her 3 times. The last time she was given a pasar and sent to live in a nursing home. It was determined to be too dangerous for her to come home. That was very hard because i believed it was my responsibility to care for her but i came to terms with it and she remained in the facility for several years. I couldn't bring myself to take the chance to bring her home as the last two breaks she had were also centered around health issues she couldn't face and so she had almost died. She had also become increasingly violent and unconcerned about the welfare of anything. So if I brought her back knowing it could and very likely would happen again i would be responsible if her or someone else got hurt. I just couldnt do it. But increasingly my mom spoke if it. The next thing i know her brother who had moved back to the state and who had been awful to her my whole life talked her into revoking my dpoa and took her out of the facility. He spent the next 5 years passing her around from sibling to sibling whoever would take care of her. Until collectively they decided they didnt want to do it anymore and one by one they left her alone older and now with several health issues.so she called me and begged me to take care of her again. At first i said no.. after the torment her siblings had inflicted on my family the entire time they had her and after feeling confused and betrayed by her for going with someone who had treated her so badly i just didn't want to do it again. I had given my all and my family had given and suffered but we talked and we couldnt let something happen to her so we stepped back in. Things had been going well.

Weve been working on her medical problems and the mental health is stable and we got her in a nice low income apartment complex for elderly and disabled people. But her mom passed away and they were never close and she says she was never close with her siblings but before she gets old and passes she wants to make every effort to have relationships with her siblings. Now i have tried to look at all of this from her side and i know the nursing facility was a nice place but its not home and it gets scary and i wouldn't want to live there if i was as stable as my mom was. So maybe she just did the only thing she could to get out and from the sounds of the last years she has been basically the butt of jokes and the one cooking and cleaning. Everything else she had to figure out on her own. She seems to truely appreciate everything i did for her and am doing for her. And i have told her i respect her decision to have relationships with these people but i do not want to be part of it. And that my family specifically my boys are to be left out of it . Im there for her and her health. But her heart issues have been worse lately and all of a sudden she is calling this brother after appts and getting his advice. He laughs at her and says hurtful things and makes recommendations about my family and her health and care and she gets upset and calls me and says he said this ,he said that ,we should do this. I cant change him, for that matter any of her siblings. And i cant seem to change her commitment to them but even her homehealth nurse has said how hard it must be for me to be constantly undermined by him. And dealing with all the doubt and confusion he brings her. I dont know what to do. Plus my family is middle class and her siblings have money and power in a small town. He hasnt and as long as im there he wont be involved in her care but he just is at her all the time commenting and poking. My family thinks he just is trying to cause problems between mom and I and get me to leave. Its a good point and at times I have gotten frustrated and asked her if she felt he should take over. She said i was the only one who cared enough to take good care of her. So I just dont get it?