Rights of a Widow (with 8 yr old Child) on Self Acquired property of Father-in law...

Case Description : The Property is in the name of deceased son's father and father (70 yrs age ) is still alive along with Wife (64 yrs age) , a divorced daughter, a daughter in law with 8 yrs grand son... 1. Son died due to chronic illness , he was working for a private organization. 2. Son only supported them financially as parents are not withdrawing any kind of pension. 3. Daughter is divorced and also working to support parents little financially. 4. Widowed Daughter-in-law is also working in a private organization and has a son age 8 yrs. Son's Father has a self-acquired property in his own name and in which the entire family is living. Father has already made a will that after him the self-acquired property will be in the name of his wife... Now, my question is as the deceased son's parents who are not withdrawing any pension from bank nor they have any source of income and today so as to secure themselves financially they wanted to sell there self acquired property and purchase a new house in a very low amount and whatever is left after purchasing they will keep that in bank as in to financially secure them for future . So, what will be the right of widowed daughter-law on the self acquired property of her parents-in-law ??