Between a Rock and a Hard Place

I live with my boyfriend and his family after a falling out with my own.

His stepdad is incredibly abusive towards his mother and 7 year old brother. He's threatened to kick them out multiple times and has destroyed their property in rage.

Today, I woke up a bit earlier to see my boyfriend off to work. I went downstairs to make coffee. I watched his stepfather went upstairs.

His brother took his stepbrothers Pokemon cards because he was being a dick, all of which evidently are $5,000 worth.

His stepdad started freaking the fuck out and telling my bfs mother and brother that he wants them out of the house and started smashing stuff around upstairs. His mom starts hysterically crying. I went back upstairs and texted her that I'm not calling the cops on him at 6am but I have to do something about it because I'm not having my family put at risk over holographic pieces of paper.

I tuned them out but all I could make from the argument was that they were going back and forth about the blame.

His stepdad starts getting their daughter ready for school and his mom started freaking out on his brother for stealing the cards. I came downstairs to try and get him away from her so she could calm down and collect herself.

His stepdad comes back in with their daughter and his mother just fucking lost it. She starting screaming and crying and I couldn't do anything about it.

I know I need this issue to be resolved but I don't want to risk them not having a place to live.