There's a term I've seen used in the UK, NEET. Not in Employment, Education or Training. I feel this is a big problem in our culture, but that's a much bigger discussion to have. How do you begin rehabilitation into life?
The greatest measurement of a man's happiness, according to recent science, is purpose. And in most cases, that's a job. Jobs can be scarce, and studying may not be supported with loans, and even if they are, one may not know what they want to learn. The overlooked option here is volunteering. You don't get paid. But you do get a sense of purpose. And when you get busy, you get your life together. It also looks very good to future employers.