you clearly care and love him a lot and want to provide with the best opportunities here. I'm sure you'll figure something out but you know, talking with some professional if you think it's needed is no shame!

and wow 6 kids....

Only 21? Give him time.

There's plenty more processing that can take place before enough philosophies will snap into place. Once he's ready, he'll go do his thing.

Make sure he knows you truly do care about him; not just the idea of him.

Oh, and be aware of the "gothic" type lifestyle. Not specifically gothic clothing/subculture, but just the idea of being a bit less mainstream in thought and feeling.

It could be that he is filled with a dark hatred of society, humanity, etc, and all that other stuff that young, intelligent, and somewhat isolated people might feel. 

As the darkest writer, the Heretic Kitten, I approve completely of the quiet, darker sort of personality.

There's no reason that every single person needs to be some smiling character, or boisterously happy fellow.

It's good to have some quiet, mysterious people who just absorb knowledge all day, and grow more and more wise, until they achieve a certain point where they can put their wisdom into action.

I think that readers generally develop extremely effective philosophies, because in my experience, it feels like I did. 

I wouldn't push this person to have a horrible job or anything either. Crappy jobs will just crush this person, and make them miserable, so demanding rent could do more harm than good. 

Not all people value shiny things. Some people see money as fetid waste, just a shiny stone that moronic apes value, but that has no value compared to the knowledge of books, philosophies, and science.

Of course, in this world, it's said that money is the key to happiness. I'm sure any person who reads books often will begin to stumble upon the harsh reality of reality. 

But letting them do this at their own pace will yield a much better result than forcing corporate slavery onto someone, just to have them "build character."