Property distribution among Two bothers and one sister.

We are two brothers and one elder sister,all are married. Our father is alive but mother passed away. Our father worked as Govt Employee have nominated his whole PF income in three equal parts after my mother passed away. My father had build a house ( land bought in his own wealth) a which is so designedly build as we the two brothers can stay in separated entity but the whole structure being in one compound. Our father belives that he gave a equal amount wealth to his daughter and therefore after his death no clash will happen in future there is no requirement of Will. But our sister want the portion that was build for our father & mother and with the guest room. I want to know – 1. Can they have any right to take the equal portion in the eye of law ( also in the light of recently passed order of SCI) 2. Can they that have any right to devide the amount that is presently my father is using for his own treatment and maintain all other things and that will be undecided by my father.