The only thing I can say is this. I know a man that is married to a woman that has 6 children for him.. I really don't know how her madness started but till today she is still insane and she is always on drugs..
The man is a church member and he is still leaving with his wife till now I'm typing his message.. I mean there was a time this woman will come to church and start embarrassing the man, she will be snatching snacks from children and all that,so the man stopped taking her to church.
I mean they are leaving together and the man has never cheated on this woman,i know because we live close to each other..
So I suggest that since your brothers wife's madness is not chronic, he can start giving her drugs to control it.. Please take her to a psychiatrist so he will tell you guys what to do..
If your brother was the one in her shoes, will you be happy if she left him,???