If he keeps giving her money, I don't know that you can do a whole lot about that. That would make me angry if I saw it. Personally, if she owes him X dollars, I'd haul her back into court and take it out of her hide. She wouldn't get anything, would lose her share of the house, the car he could turn in, etc. It wouldn't be comfortable for me to have him figuring out/fighting with her so close to me. Sounds like he's still working it out for himself.

It would be hard too, if he isn't aware of the ramifications of your dx and things don't go well there to then ask him to leave later? I'd be afraid to invite one of my brothers in (I have 3) to live with me.