abuse and negligence of my grandfather how to proceed legally

My grandfather is almost 85 years old. His son, daughter-in-law, and grandsons are living with him in his house. Since last two years, they have been showing utter negligence to my grandfather. Recently the have even stopped to provide him proper food let alone proper medical care. My grandfather has repeatedly asked his son to leave the house but he every time denies citing his expenses for some repair works of the house. My uncle doesn't allow my mother or maternal aunts in the house. My grandfather went to the police last year when the situation became really worse, the OC of the local police station called both my grandfather and his son to the station, his son apologized and promised that everything will be fine but nothing has improved since then. I want to know what are the options are open for my grandfather. If my grandfather takes a legal route to make my uncle leave the house.I want to know what are his options? If we go to court how long it will take for a resolution?