Abusive mentally unstable unsocial wife

She is my brother’s wife who left him one year ago.She doesn’t return or file for a divorce.The family members from both sides tried to convince her to go for counselling but to no avail.My brother loves his son very much.He is very much depressed now.When my parent went to convince her, she threatened that she would complaint to women’s society and make my brother lose his government job(bank officer).She is taking pictures everytime we visit them.She stays at home and doesn’t even do simple household https://chores.My mom used to take food to her bedroom and she is ok with it.We adjusted in every way possible but suddenly she left home due to to a small quarrel with my brother regarding cancellation of a planned tour.She is not social.She is the only daughter.Her father is a very good man.She is not in talking terms with him too .Her mother has been an abusive wife too.Her father confessed this and it is she who is spoiling this relationship .I’m surprised to see her own mother spoiling daughter’s and only grandson’s (4 years) life.Since it has been one year , we have no hopes looking at their behaviour.Please suggest how to get rid of her without any hassles. Does she want us to initiate divorce so that she can make it more ugly? Please suggest.