Help me help my friend who’s mom is causing a lot of harm

Hi, I’m not sure how to help my friend other than being there for him, but seeing his situation breaks me. My friend is disabled and his condition has caused a lot of difficulties for him to find his path in life. But it’s not just that. On top of it his mom is emotionally torturing him daily, and I’m so concerned for his safety. This much stress put him in the hospital years back and he was unable to leave his apartment for 3 years after that. He’s such a bright light, but he’s frail. He doesn’t has the support he needs and I feel limited in what I can do. Because he’s so sick he has had to rely on his parents for financial support. They have lots of money, but his mom treats the little money she gives him as such an imposition, and she’s constantly reminding him of how his illness has cost her in life, how she didn’t go on a trip or bought a second home because of him. He doesn’t puts boundaries with her, he is so hopeful thinking he can change her. He puts so much energy into this. But she’s over 70 and I’m not sure she will change when she’s been like this all her life. Her other son went no contact with her but my friend can’t because he needs help financially from her. I’m just so concerned. I’m probably not explaining the whole situation well but if you have experience with a toxic mom please let me know how to help. She only sees her pain and doesn’t care about the pain of her family. It’s like she wants him not to get better so he can’t leave her, but I’m so scared he’ll get severely sick again dealing with a 9-10 stress daily that he will not recover.