Seek Divorce from wife for brother

My brother got married ~6 Years before . Since his(Elder brother) marriage he & my parents are facing humiliation by my Brother's wife in all possible ways .We all tried to conveyance her to consider us as her family , But she never perceive herself as part of our family . My brother is doing well with his earnings before 3 year so he returned to hometown & used to UP & Down (travel )Daily for his repair shop ( rented shop ) from Nagpur. She has never accepted his earning level & always compare with My sister and my wife who are earning better than my brother , etc . Her parental has intervention at high level in our house matters and they never let her think apart from parental . (A common issue with less mature women , when she allow or seek intervene from her parental in husband house ). She wants to stay away from my parents and argument every alternate day from long time , But due to his financial condition He couldn't . They are having two daughters of age ~3 & ~5 . But still we are just waiting with all possible ways to make her understand the reality and his dependency on me & parents for financial part . He has express his frustration many times , and I have great worry for his daughters if do something wrong with himself . In my view , he has no other choice other than get separate from her . Pl help me this .