ancestral and acquired property for daughters and second wife

My wife has no brothers but got a sister who is also married. My father in law married again when his first wife is alive. He had ancestral property a plot in which he built a house. His first wife had expired. He had other property which he is refusing to give to his two daughters but trying to include his second wife's name in the ancestral property along with daughters name. His second wife has no children but wanted to grab both ancestral and other properties of her husband denying natural rights to his daughters. My father in law obliges his second wife but not his own daughters. Can my wife and her sister sue their father for exclusion of second wife's name from ancestral property, though it is mentioned in the will? Can they try and get their father's other property, that is given to second wife, after her death? Or she will have rights to transfer as per her wish? What are rights of my wife and her sister vis a vis their step mother? My father in law refusing to transfer ancestral property rights to his daughters exclusively and wants his share in the property till his death and wants same share to his second wife after his death. He is likely to die early as his second wife is at least 20 years younger to him.