Can a family member who has abused mom move in together as her caregiver - family member is a paranoid schizophrenic?

I would think if the doctor has a record of this abuse, as a Mandated Reporter, he/she would have been obligated to report the abuse to Adult Protective Services. Because there is a record, contact an attorney and see if you can get a restraining order against him. If you don’t have Power of Attorney, I’m afraid your options are limited.

I filed for a restraining order but had to postpone it. Then was able to get mom back home but he got her back in no time from taking all her money she had nothing to live on. I don't have a POA. She's loosing her home because of him. And he is preventing me from talking to her. She wanted to save her house when he found out she want to he threatened her some more and she's afraid to talk to me. I have tried APS they are absolutely worthless in my county. Police same thing. I don't know how a restraining order will work when he has been keeping her at his little apt. If I do that I won't be able to ever talk to her if I got the chance.

Why did you postpone your application for a restraining order? When was this?

Is your plan still to return your mother to her own home, with the reverse mortgage on it, with - what? - support and care?

I think you might get further in discussions with APS and the police, and other agencies too perhaps, if you see your mother and your brother as a package and try to stop blaming him in your head. E.g "he put her into debt" "she has been programmed" "he's turned her away from daughter". Your brother is mentally ill. Stop attributing his misdeeds to intentional strategies.

Your mother loves her son. That is bad news for her, I agree - she would be richer and safer if she allowed other, better qualified people to take over his care - but until you align your plans with his welfare as well as hers she will undermine and oppose everything you do.