My brothers girlfriend regularly abuses him verbally. She says horrible awful things to him (now uses the baby as emotional abuse) is incredibly controlling as to who he speaks to and is always accusing him of lying about his whereabouts and regularly has to prove where he is.
She's 6 months pregnant and they're about to move into a flat together. I've pointed out that she shouldn't treat him that way and if the genders were reversed everyone would be saying it's an abusive relationship but he doesn't see it. He just says that he finds it stupid and just ignores he vicious rants until she's calmed down and apologised.
I've tried to point out how toxic the relationship is but it falls on deaf ears. So do I now just stay out of it until he realises that's it's wrong and leaves? I'm worried about it escalating to psychical violence but that's just probably my protective instinct. Thanks for any advice.