Divorce

One of my friend is in trouble. It was a love marriage of theirs. They got married 15 years back despite of opposed by their individual families. They were in relation for 10 years before marriage. In beginning they lived separately but afterwards everything was fine & they started living together with my friends parents in the same house. They have one daughter of age 13 years. 2-3 years back my friends father passed away and his mother inherited some of her husband's property which she transferred in the name of her son(my friend). From last one year my friends wife is irritating him to stay seperate in another house leaving his mother alone which he does not wish to do so. Then somehow he made up his mind to stay seperate for some period of time as per his wife's wish. But now 15 days back his wife sent him a letter by speed post asking for divorce and share in the property which he has received from his mother or else she will file a domestic violence case against him. He also discovered that his wife has made arrangements of shifting alone to another house. She has also sent letters to the societies where he owns the house(inherited). He feels that she is just pressurizing him for property and any how she is going to take divorce. He tried to convince her that if she wants the property as legal wife, she has to stay with him in the same house for the sake of his daughter. He feels that she is a very selfish person and is list concerned about their daughter. In these circumstances, please advise what can be done.Can he file a case against her for mental torchure & harassment for property.