I saw one of my male flatmates get proper slapped by his girlfriend when I was in the living room yesterday, I walked in just as about to leave putting food in my bag, I asked him if everything was okay, I can tell by looking as his eyes he was upset and she was proper angry.
He told me to leave it, that it wasn't my business to get involved and I said if you want help getting rid of her call me so he knew I had his back.
Later on when I got back he said he puts up with her hitting him, he is a strong lad so he take it but to me if a girl truly loves a guy she wouldn't hit him and I see as bad as a man hitting a woman. I don't know his girlfriend that well but she seems very aggressive and angry, everything seems to be her decision and he just a slave to her demands, I have never seen once go out her way for him, she is attractive so she uses her image to get what she wants, he seems be in love even though she is a total bitch towards him.
I told him it doesn't matter what someone looks like and their gender is, nobody should be the subject of violence. I want him to get rid of her, yeah he may not find someone as attractive but there is a lot nice girls out there who can treat him a lot better.
How do I get him to listen to me? I was thinking about telling his sister so she can have a word as he might listen more to a girl rather than me as I think he's easily led by girls. what is the right thing to do?