Exempted receipt of Gifts by Individual - Proof - Income Tax

U/S 56 (2) amounts received consequent to WILL is exempt even if the deceased does not fit into definition of relative for the legatee. The executor of the WILL has released money to legatee, but he is not willing to share the copy of the WILL for obvious reason (Privacy). What other proof our group can think of to support the legatee to get tax exemption since mere confirmation from the executor may not be actual proof of succession through WILL.