Apparently he has limited assets. It might be feasible to give the keys to the bank and walk away, but I'd certainly get professional advice. There could be a number of ramifications including any assets when he dies. Possibly they could attach his income and force him into a different facility.
Find out his options and then let the bank know. They may be flexible and not want to own the MH. But they may drag their feet. He may also be responsible for continuing expenses until it is sold. ie In Arizona banks do not change the title on a foreclosed home. Therefore all maintenance, taxes, etc remain the responsibility of the home owner. Some of these will never be paid by the bank.
2009 Holiday Rambler 42' Scepter with ISL 400 Cummins
750 Watts Solar Morningstar MPPT 60 Controller
2014 Grand Cherokee Overland
Bob