If your roommate emotionally abused their SO would you say something?

A little back story

They are not just roommates they are close family-friends

We are all young 19-21

It’s pretty bad.. I’ve grown up around a lot of physically abusive relationships and ive honestly never heard someone be so mean to their partner. I do have PTSD and hearing him talk to her like that triggers flashbacks. He treats her like a slave. It makes me soo sad and I don’t want my baby growing up hearing that and think that its okay to treat/be treated like that. Its hard cause it’s been awhile since they moved in and no one has really said anything about it. A couple times someone kinda said something or he see us with shocked looks on our faces he would say “well she does.. & she never listens to me” & just try to justify his actions.. I don’t know if we should talk to him or just mind our business..