Tbh think IABU.
BILs lovely long term GF (5 yrs) ended it with him in Jan. BIL immediately finds new GF (definitely nothing going on before the break up). Their relationship has moved really fast. Within months they were talking about buying a house together and he moved in with her and parents after 3 months. They're now renting together.
Problem is new gf is awful - immature, selfish, massive drama queen. She's ruined a couple of family events including our wedding by throwing tantrums. She has no interests and doesn't like BIL having any either. We used to be v close but have hardly seen him since they got together. He seems happy now but long term we don't see how he can be if she won't let him off the leash and seems to need to dictate everything in his life. She wants to get married soon (has said this openly) and we're terrified this will happen.
WWYD? Would you say something? Should DH be the one? (He is DH's bro but he and DH not always good at talking about this stuff whereas we had a v open relationship).