Father's property gifted to one of the children

if father of ur grandfather gave said property in return of some favour and if there was a document of any kind it in that respect it became the absolute and self acquired property of ur grandfather which he could have dispossed off in the manner he liked. if so, once gifted to ur aunt, it became her absolute property and no one else can claim any right or share in the same. However, if the property given in return of favour was ancestral, it could not have been gifted away by ur grandfather and other siblings too had a right. u can approach the court for getting the property partitioned but will be difficult to convince the court as long long time has elasped and a question of limitation may come into picture. it is also to be seen whether the gift deed was registered one or not

If a ur grand father as aquired the property for a consideration of his own. the property becomes his own he can gift it to anybody he wishes.