Are they authorize to claim that property or not.
Legally speaking your grandfather do not have any documentary prof for purchase of this land nor he is holding a title document in his name, therefore he cannot be deemed to be the owner. However the long possession and the evidences for possession and subsequent developments over the land i.e., construction of structures over it and the same devolving on his legal heirs upon his death are some valid reasons and evidences to claim the proeprty at least by adverse possession. Besides, the tax receipts and other relevant records will make your father entitled to the title by adverse posssession. Their clainfor the property to be denied by this stand
• If they are authorize in that case they will authorize to claim only for land or built home also because in will mentioned land.
Only for the vacant land...
• if they claim can we sue them asking for amount of built house, maintenance charge and paid taxes which we have paid in last 60 years
It depends how you put forth your case before court.
Note : there is no documents and complaint during this 60 years tenure to evacuate said place, we do not have any documents and agreement of dealing that land.
This is both advantage and disdvantage