Land of ny Grand Father.

Hi, this question is related to the case which is being filed on the share of property which has not been provided to my deceased grand father. - My grand father after marriage moved to a different place B from the place birth A for which the case is file. - He passed away in 1970s and his wife (my grand mother) passed away recently. Unfortunately we could not find any ID proofs of my grandfather as he died in 70s. - The 4 brothers of my grand father divided the property in place A among themselves without mentioning my grand fathers name. - Now that we have filed a case for the right of our grand fathers property, we do not have any ID proofs related to my grand father. The brothers are not allowing the people from place A to be the witness in the court to confirm my grand father identity. - As my grand father died in 70s, there is not much identity proofs with us. - how to move further in this case? Can we appeal and request the court to send a team to Place A to investigate my grand fathers identity?