90 years old and wants to enter into a 25 year contract ----------- sounds like he wants to live to be 125.  At that age I think he should go with the old saying "in God we trust, all others pay cash".  I would try to talk him into either getting the cash up front or go with the plan of letting the heirs sell it at a stepped up basis.  Is there any specific reason why he wants to go down the 25 year road other than he has a potential buyer now?