Brother hit my SO

My SO got really drunk the other night and when he's drunk he can be really argumentative.. long story short.. we got into a bad fight. I was visiting my brother over holidays and he saw the bruises on my back and face and flipped shit. went tracked down my SO and assaulted him....SO called the cops and now my brother is in Jail...

I just don't know what to do. I love my SO and my brother. I didn't want anything like this to happen....the only family I have is my brother and dad..so my SO means a lot to me for everything he's helped me through...

He just gets angry sometimes but we're working on that. He stood by my side and still does while I overcome my drug addiction ...so I'm wanting to show I can stay by his but I want him to drop the charges against my brother...

I'm just so confused...I don't know how to bring it up to him without upsetting him

Edit: I have no family to turn to now... I have no where to go.. my dad is a couple hours away and I can't call and tell him what's going on ... I don't want him to be disappointed in me. I should of neve gone over to my brother for holiday.... I should have waited till xmas.

I can't bail him out my SO took my money... I just need to know what to say to help change his mind...please