Revocation of gift deed

In 2009, my father has done gift deed settlement to his mother (my grandma) without my knowledge and my mother's knowledge due to family fight, when that time I was major. Because of the family fight, my aunty (my father's sister ) planned to make gift deed through my grandma to ask more share on the particular property. Note: the partition and settlement has been done in 1999 as well. Now the my grandma and my aunty demanding to give share more or occupy the whole property. Otherwise my grandma is going to write settlement on her name. But still the patta is in my father's name. Be he is holding the original gift deed document. My grandma and aunty tried to transfer the whole thing to her name. But not happened. Since the original gift document is in my father's hand. It is not been done. On the above story.. 1. This is been known to me only before 1 year, what action i can take to retain my ancestor property? 2. Also my father now joins to me, seeking to revoke the gift deed which he has done. Is revocation of gift deed possible by my father? 3. Now we as a family expecting that ancestor property has to come to me and my sister, not for my grandmother and aunty. So please advice on this...