Immature wife and her cruel family torturing groom

Hello Sir/madam, My brother got married in 2009 and he has two kids (4 yr old boy and 18 months old baby girl). My sister-in-law's behaviour is completely unpredictable and she frequently fights with him and neighbours for no reason. So far he has moved to three different houses. She does not respect anybody in the family and others. She does not maintain the household properly such as cooking, child care, cleanliness of home and worse social attitude/adaptability etc. Their elder son has not gone to school for 5 months now. What ever little money my brother earns..she spends them on beauty parlour. She blows any small problem out of proportion and unnecessarily fights with neighbours and her husband which results in frequent movement of residence and puts enormous pressure on my brother. So far she has dragged my family to police station for three times. My brother does not earn much money but he gives his entire salary to her as he does not have any bad habits. But still that is not enough for her. If anything does not go in her way, she files police complaint alleging my family and particularly my mother is the reason for the problem. Last time we already clarified with the police that my brother lives alone and we don't interfere with his family affairs. All the dowry she brought were already returned to her family by her for safe custody and my brother does not give any of his earnings to my family or my mother. My brother and my family is constantly under pressure and tortured. Our family reputation is already irretrievably damaged. The kids were the reason for not considering divorce previously. But this has become unbearable now ..she does not want to be separated..her family also does not want divorce. But my brother has made up his mind to live alone rather than being with her. Note: There are many things i could not go into detail here due to long narration. Her family is also threatening us with false cases if could not satisfy their demands. She also wants major part of family property and money to be transferred on her name. They don't care that the family has still two sons to be married off. If you could clarify the following will be helpful. 1. Can a husband file for divorce for the above reason? Or How to do it? 2. How long this kind of case will take to be resolved? 3. If possible, how much this case could cost (Approx)? 4. What will happen to kids? Is it possible to retain them with father? 5. If divorce is granted..What about Alimony. Is it only calculated based on Husband's earning or based on family income. (Two unmarried brothers also are earning in the family) Thank you very much.