Harassment by mother-inlaw and husband.

My daughter got married almost two years ago and got a son. Husband is working out of Kerala and my daughter is doing post graduation in Kerala. My daughter is College topper for engineering. Husband blindly believes whatever his mother says and shouting on wife over phone frequently for no fault of hers. Whenever she visits husband's house mother-in law not providing proper food and sister-in law also insulting her and mother-in law also joins in insulting her. The entire house will be kept dark and not allowed to switch on the light. Mother-in law is a widow and only ladies are staying in the house. Mother-in law is asking my daughter to bring gold and money from my house frequently and also threatened that she will face dire consequences if he discloses this to her parents. All these happened in the presence of the husband. When my daughter asked husband as to why the mother-in law is behaving like this, the husband told my daughter that his mother has told the correct thing only. The husband will also not buy things for my daughter and whenever she ask to buy anything he will tell her "you get it from your father and you are not sold to me!" Mother-in law will also not allow to buy anything to my daughter. My daughter unable to withstand the torture and insults, do not want to visit husband's house and meet mother-in law and sister-in law any more and want to get separated. Can we file a suit against the husband and mother-in law for the harassments? Your kind advice is requested please.