is it self acquired property of grand father? if so on demise of grand father property would devolve on grand mother and his children . grand daughters/grand sons have no share in the said property .

Grandsons/granddaughters have share in ancestral property of their grandfather.

Whether the property is the self purchased property of grand father? If yes, it will vest in his widow and children after his death. As such, neither grand daughters nor grand sons have any share therein.

yes if property is ancestral