Adding to my post above, I'd probably deduct it. I don't think the character of the loan or its terms are changed simply because it was inherited. It is still a reverse mortgage, and if it is still in the estate the administrator or executor would handle it the same way the decedent would if still living, and in the heir's hands he is still bound by its terms and is required to pay it off within a certain time frame.
From pub 936: Reverse mortgages. A reverse mortgage is a loan where the lender pays you (in a lump sum, a monthly advance, a line of credit, or a combination of all three) while you continue to live in your home. With a reverse mortgage, you retain title to your home. Depending on the plan, your reverse mortgage becomes due with interest when you move, sell your home, reach the end of a pre-selected loan period, or die. Because reverse mortgages are considered loan advances and not income, the amount you receive is not taxable. Any interest (including original issue discount) accrued on a reverse mortgage is not deductible until you actually pay it, which is usually when you pay off the loan in full. Your deduction may be limited because a reverse mortgage loan generally is subject to the limit on Home Equity Debt discussed in Part II.