Thank you! I very much appreciate the thoughtful response, and I concur. 

He definitely can/could be claimed on his parent's returns, regardless of whether or not he will be or has been. 

As far as the books/programs that I vaguely referenced, I didn't have anything specific in mind other than that I have long been aware that this individual is off the grid. Who knows what his older years will bring ? As you have noted, no work record, no participation. His parents are in their 80's and will leave assets but as we both know, that can be a blessing and/or a curse, especially if there isn't income. 

I hope he is wise enough to reach out when that time comes.