I agree that Penny’s idea sounds really great. My parents definitely had to help me out during that time in my life. I dropped out of college 3 times and had a hard time with jobs. Mainly because all the jobs I could succeed in (service-based, working with my hands) paid and treated me poorly so I would get so fed up that one day I would just quit.
It took a while to figure things out and it didn’t help that all my friends seemed to be light years ahead of me with the whole “adulting” thing, but without the help and most importantly, the love and emotional support of my parents, I would have had an even harder time.
I would add that it’s important for your son to know that you want to help him get to a point of self sufficiency, that you understand that it is particularly challenging for him, and that you know he can succeed.
I hope your family finds a solution that works for you! The fact that you are even here looking for help says a lot.