Bro's girl wont stfu

My boy and I have been super close for over 10years and we're like brothers at this point. He has been dating his girl for 3yrs now and tbh I've never been a fan. She's young and immature but my homie loves her so I'm happy for him.

Lately we've been hanging out all three of us alot, drinking and sht, and whenever my boy's girl is drunk she tells me shit like how my boy can't make her cum, or she asks me what my kinks are. Mind you this is either when my bro has left the room or blacked out. And I've told her repeatedly thats this is TMI or not a conversation I'm tolerating. She's done this 3 times now and I'm now concerned.

I'm not sure what my next move is, should I keep lengaing or tell the bro.

Edit: I'd never smash ata akue the last being on the planet. Not my type at all. And the reason I've not told is because morio ako deep. This is his first real relationship. But I've told him to end things tbh before because of other situations na haskii. I feel like this would crush him. But I'll record the next convo for sure