What a horrible man and his family? Yuck. Definitely NTJ but you may be a jerk if you continue to put up with his/their behaviour. You are his wife...its about time he started behaving like a husband. If he doesn't....might be a case of letting him spend as much time with his family as he wants permanently.
NTJ but, I wouldn't give the diamond or ring away either. Simply because if you're brothers relationship is solid, it shouldn't matter what size stone is in that engagement ring. Good luck however you decide to go forward.