I've been with DP for 13 years. I have a 16 year old DS and he has a 17(18 at the end of the month) year old DS. We all got on well until he turned 9/10 and his mum started telling him DP preferred me and DS instead and that I was the reason they split up. I suspect this was due to us getting engaged. DS sees DP as his dad and calls him that but SS would constantly say he isn't his dad and would try to hurt DS. We would deal with it at the time.
He moved in with us in Feb as he was saying his stepdad hit him but his mum didn't believe him. DS attempted suicide in August and he very nearly did but thankfully his friend reported it and he was ‘fine’. SS was annoyed as MIL (so his gran) had passed away and so he accused DS of doing it for attention. A few weeks later he told me and DP that he was gay and that was partly the reason. We were fine and his mental health seems to have improved. He asked us not to tell SS so we didn't.
He started college and met a boy. He came out to SS as he was worried about him seeing them at college but since then SS had been homophobic towards DS. Introducing him as his “gay brother” even after DS and us have told him to stop multiple times. Asking why he chose to be gay. And refused to share a room with him on holiday. We've spoken to him and he agrees to stop or just argues, but then he carries on.
DS had his boyfriend over today and he gave DS his Christmas presents, boyfriend has got me and DP a present and SS (A bar of chocolate). SS has been teasing DS by saying that his bf fancies him as he got him a present even though they have hardly spoken and then tried to upset DS by saying he saw him kissing another boy. DS shoved him and went to his room. We spoke to SS and he agreed to apologise but he instead carried on teasing DS. DS has gone out upset.
DP has been thinking of asking him to leave for a while but now has decided he will but I'm unsure if that's the best thing as I worry his behaviour will become worse towards DS