Widow Mother denies to give equal share to her only two daughters

Sir, my grand mother has only two daughters and no sons. Unfortunately my grand father died recently due to his health problems. My mother is the eldest daughter of my grand mother. We had no properties and wealth to receive from our forefathers. My grand mother is a class-4 state govt employee. What ever the wealth we had at present is solely the hard earned money of our grand mother which accounts for near about rupees 2 crores. Our mother is the eldest daughter of my grand mother and i am the only son to my mother. My father died in an accident recently. So My self along with my mother living at my grand mother's home since last two years. The actual disput realised by me recently while looking at my grand mother's LIC policies. Our uncle (husband of 2nd daughter of my grand mother) said to be threatened my grand mother to notify her younger daughter name as nominee to receive 100% claim amount after her death. After seeing this bond paper I argued with my grand mother for not including my mother's name as nominee to receive 50% share from claim amount. Than onwards she started hating us, found herself busy in quarreling with us for no reason. And now my grand mother forcing us to leave her home, and says she will not going to give even a single paisa to my mother from her from her properties. She is threating us writing a will on the name of her younger daughter to enjoy her properties 100% after her death. My grand mother showing partiality in treating my mother on par with her 2nd daughter. We are helpless, and we are not arriving to any conclusion? Kindly suggest suitable steps by which we could get justice.