Legal Question in Real Estate Law in India

From your question 2, I am assuming grand father is alive. Second, brothers, younger or elder, have equal status for inheritance. Please note during the life time of owner grandfather, no one, can compel the owner to sell the house, irrespective of what one has. if the property was self acquired property of grandfather, then, grandfather has every right to dispose it in any manner he desire. He may gift it or sell it during his life time or make arrangement by writing a WILL for distribution after his death.

Ques 1: According to law , do my uncle has the authority to force us to sell the house?

No, he has no authority whatsoever to force you/your father/grandfather to sell the house. In fact you have no authority to sell the house anyway. Electricity and water meter do not give title.

Ques 2 : Ans Is it possible that my grand father gives this house to only one son ,when we dont have any place elsewhere?

If it is self acquired property of Grandfather, he can give it to one or to two or to all or to none.

Ques: What we have to do under these circumstances?

You only have to stand in the good books of your grandfather so that he does not exclude you from his mind and WILL or you may get some share as gift during his life time.