Ok this is going to be a long post but I need to give the backstory. So my brother has a few issues. He met his now wife when they were at school and they were obsessed with each other. After a couple years our parents suspected he was physically abusing her and forbid them from seeing each other but they ended up running away and moving in together in another city. 7 years later she became pregnant with their first child and they got married. On the outside they seemed like the perfect couple but after their second child was born two years later his wife began confiding in me that he was cheating on her. She said she couldn’t talk to her family about it cos they would force her to leave and that was something she couldn’t do. I was disgusted but she wouldn’t let me confront him about it. He eventually went public on social media with this new girl - all whilst still living with his wife, she was still taking care of him cooking his meals washing his clothes etc etc. This is when I confronted him, he said he and his wife were no longer together and were just living together for the children. I knew he was lying so he refused to speak to me because apparently I didn’t want him to be happy. This went on for years. His wife barely had any friends and she only ever went out with the children. He’d get into relationships with one girl after another, all whilst still going home to her. She knew everything (and told me) even though he thought she didn’t but still she wouldn’t leave him. She said it wasn’t because she wanted to be with him it was because she was scared of him. I tried everything to help her but it was no use. Eventually got a really good job in another country and a few months before they were set to leave they moved into separate houses; Her and the children with her family and him with his girlfriend. This is when his wife realised she was ready to leave him but it was too late cos they’d prepared to move away. They went but he couldn’t get a visa so he came back. She plucked up the courage to tell him she didn’t want him to go back and he accepted it as long as he can visit the children and they come and visit him. His wife is now like a new woman and I’m so proud and happy for her. That dramas ongoing but here’s where the concern comes in. He’s now living with a new girl, 11 years younger than him. He says she’s as amazing as his wife was in the beginning but claims she’s got mental health issues. I keep asking him what it is that’s wrong with her and he says she’s crazy and she “switches”. An example of what he classes as crazy. One time they borrowed my car to go shopping, I drove them home and when I got back to my house I realised they’d left milk in the car. I messaged my brother and told him and he sent back angry faces and said he knew she’d do this. I said it’s fine I’ll just bring it back down. When I got there she messaged me apologising and saying she told him she’d just get another I told her it was fine. When he came outside for the milk he apologised and said it’s cos she’s “switched” again. I said I think it was a genuine mistake to which he said “no she’s been acting crazy all day, she said she didn’t want to put the washing on spin because she couldn’t be bothered waiting for it.” I was confused as to what was crazy about that but whatever. He says she’ll come in from work and say “it’s hot in here!” And close the windows - to him that’s crazy cos apparently she wouldn’t do it if she was ‘normal’. If anything what he describes is like PMS symptoms because he says it happens once a month. They live together, spend all their time together other than when they’re at work and even when they’re at work theyre texting or on the phone. She doesn’t have any friends and has barely any contact with her family. She recently said she thinks it’s best if they don’t speak on the phone as much because they’re running out of things to talk about. This is another thing my brother says was her “switching”. I try to explain to him it doesn’t sound like she has an issue at all but he won’t accept that. Now what’s worrying me is this girl is seeing a psychiatrist, she’s being given medication on top of medication (for anxiety and depression) because they haven’t been able to diagnose anything. She’s even convinced she’s got something wrong with her too. Every time I speak to her she blames herself for their arguments when she hasn’t done anything wrong it’s like she’s brainwashed! I know it’s not my business but I’m so worried for her and I feel like something needs to be done before it gets worse, talking to them doesn’t get me anywhere what else can I do?