Gift deed cancelation

In which year your grand father Gifted the property?

Whether the Gift Deed was registered or not?

Whether elder son to whom the property was originally gifted is alive or not?

It is not clear as to what procedure did your grandmother adopt to cancel the Gift Deed?  

Whether the Gift Deed made by your grand mother is Registered?

Grandmother cannot cancel the gift deed of your grandfather. You grandmother is not the owner of the property so she cannot cancel the gift deed and transfer the property to anyone.