Today this owner has around 50 to 60% equity in his house which is probably worth around $300k. His monthly mortgage payments are 80% of his retirement/social security income and he is struggling every month. He wants to have options. I'm suggesting him to do a reverse mortgage so he can keep all his monthly income but I know the fees are high and the interest rate is high too. Is there anything else out there he could be interested in? I was thinking on the lines of selling the house now to an investor with a rent back option that has to be respected until owner dies or something in those lines. Has anybody done anything like that? 

If you need numbers to better understand, lets say house is worth 300k and the outstanding mortgage balance is 200k so lets say investor buys the house for 200k (to pay off the loan) and lets the owner live there for the rest of his life for free (with an attorney approved lease agreement in place). Normally this house could rent at about $20k per year, so if the owner/seller lives over 5 years investor would be losing rental income (since that would make up for the 100k discount he gets up front when buying the property) in comparison with another tenant he could have in there and continue to pay 20k/year. At the same time investor could gain on house appreciation or land value so investor might be motivated to risk  loosing rental income after the 5 years.