The land which your grandfather purchased in your father’s name, if he gave it to your father and made him its owner and your grandfather withdrew his control from the land then that land solely belongs to your father and the other heirs shall have no right in it. But if the condition is not so i.e. your grandfather did not give that land to your father’s possession and ownership rather your grandfather remained its handler and owner throughout his life then in such a case that land became inheritance of your grandfather, in which all the heirs shall have their due share.
Allah knows Best!
Darul Uloom Deoband