He'll never accept it and there's nothing you can do about it. The fact that no meant maybe to him the first go around says that the only way he will be happy is if she is with him and no one else. The whole "she not trying to be my friend" fit was jealousy because he didn't know what she was doing or who she could be with and she wasn't devoting her time to him. Someone is going to end up unhappy on this one and if your bro can't handle it...tough hop! You can be reasonable for his lack of maturity.

99 Contour Sport SE MTX KKM filter, B&M shifter No res, BAT kit Green car silver hood (because silver is faster)