Reverse Mortgage for Mother-In-Law? Her mortgage is "Upside Down"?

My Mother-In-Law has sold her homes and moved four times in the past 20 years, and she hadn't planned on living this long (I know, I know-she wouldn't take advice before)...so she can manage her mortgage payments, but can no longer pay her property taxes which come out to about $400.00 per month. Her home has been on the market for three years, but has steadily decreased in value, so it is no longer worth the 265k she owes, so she can't sell. Now what? Do all homes need to have equity in order to get a reverse mortgage? What are her options? Any insights are greatly appreciated.