Lawyers/Legal: What can our cousin do?

To say my husband's cousin is going through a rough time is an understatement. She has a history of anxiety and depression. While all of this has gone on, she has also lost her mother figure in her life, one of her only support systems. She was like a grandmother to her daughters. She's also had to put down a couple pets as well.

Last fall her husband's grandfather, the man who raised him, passed away. He has been "coping" by giving up being a husband (he started cheating on her shortly after his grandfather's death) and a father (only wants to do fun things with his kids). She has been in contact with a lawyer through all of this and would like full custody.

He has become a control freak, constantly changing passwords and needing to know where she or their daughters are at all times, and needing to "approve" of things before Holly (our cousin) can do them. He also threatened to turn off the heat this past winter, with all of them living there. She feels trapped inside her own house. When she isn't home he goes through her room, for what I don't know. He's in denial that there's a better way to process grief, and also denies she has anxiety and depression.

She can't kick him out because the house is in his name. More than likely he will delay the divorce as long as he can, so he can still have control and avoid child support. She hasn't fought for the house because she won't be able to afford all the bills on her own w/o child support.

My husband and I can only do so much but we try to be there for her and help as much as we can. All of the responsibilities fall on her, even on nights she has her daughters, since her husband does nothing to help around the house or with the girls.