I don't know if it is possible, but does he have any skills he can convert and use in self-employment? My husband came home one day and said he had quit his job. We had an infant and I wasn't working. Immediately, I placed an ad in the home improvement section advertising his skills as a plumber and he got his first "job" in a week or so. We became permanently self-employed and he did the necessary things to get the proper licensing, etc. after "they" literally came knocking at the front door.
Maybe just taking some action will help his frame of mind. If he has no home improvement skills, how about car detailing, lawn care, pet care, tutoring....
Just a thought. Good luck and a big hug...5 teenagers wow! Hang in there Mom, find some time for yourself and get those teens to helping the family, too.