Property issue

We both sisters and my mother lived in a flat purchased by my grandfather. We live in with my brother his wife and two children. My grandfather passed away in 1988. Flat comes to my fathers name as he was elder son.Other uncle n aunts has given NOC on affadavit. My father pased away in 1998. He didnt make nomination n will. Then my mother became owner of the flat after giving advertisement in three newspaper and some formalities told by society committee. Now my brother doesnt pay single rupee to my mother. He and his wife are working.having good income.purchased flat in same bldg n rented. I am elder sister working with bank. My mother and sister is dependent on me. If we want to make small changes house my brother and his wife thrown away our furniture out of our flat. Sometimes my brother beats me also. My mother who is senior citizen and me has filed complained in local police st. Both of them threatenes us everytime.mother want to throw them away but they are not vacating the house saying it is inherited family.Local police doesnt help and tell us to bring court order.Pls guide us