I really need some help with this please.
My sister has been separated from her husband for about 2 years and they were divorced in the last few months. They have 2 sons, 4 & 3.
From the minute I met him, when they got together, I couldn't stand him. Which is ironic because I've liked all of her boyfriends a lot, until the one she married.
Anywaaaaay. We've barely ever spoken - he knows that I don't like him, and I live 150 miles away so it's not a difficult job to keep out of his way. It was a borderline abusive marriage and caused a distance between me & my sister.
My sister has had pneumonia twice in the last 6 weeks, and has been hospitalised both times. He had the children overnight a couple of times while she was in, and then he got bored. Once he phoned her in hospital to tell her that the boys wouldn't go to sleep
Now he says he won't have them because he's 'missing out on things'. She's been told to strictly rest for 2 weeks since she came out of hospital, but she can't. Her boys are hard work.
My mum is helping as much as she can, but she's tired, looking after the boys in the daytime and stuff.
Honestly, I could go on all day... he's just a prick.
So here's the thing. When he goes to the house, he tries to kiss her, to cuddle her - he buys her flowers..... he wanders around the house as if it's his own (he's never lived in that house, she moved there last year), he tells her if it's a mess. She's a strong old bird, my sister, but she's intimidated by him - I think over the last couple of years it's become clear to all of us that he has mental health issues.
I genuinely don't know how to help her. Does anyone have any advice? I alternate between feeling useless and wanting to find someone to break his legs. I won't of course 
Sorry this is so long. I'm just at a loss.