Didn't read all your responses, but 'meals' is NOT all you're providing for him. Room/Lodging, water, heat/AC, telephone, garbage pick-up, access to electronic usage (and the electricity to run them), free laundry facilities, a ride if he DOES go anywhere -- all these things that mature adults have to provide for ourselves are provided for him for free. You probably Shop for, pay for, and cook/prepare the food he eats. You may even have insurance on him.
I work at a job that doesn't pay nearly what I'm worth, but it is a steady income and we are always needing workers in our field (high school diploma & driver's licence required).
I agree that he sounds depressed, but you are enabling him by providing shelter, bed, utilities and eats. Nagging him only worsens it because men need to know that someone believes in them -- that they are able, capable, and competent. Start by thanking him for anything he does do that contributes to the household workload, but don't do ANYTHING for him that he can do for himself.