I have two nephews that fall in that age range with 2 more close. I spent some time with them over the holidays, the 20 y/o is going to graduate from UW with an engineering degree and is intelligent enough he will be ok, though socially he isn't great. He will live a "thinkers" life and be comfortable yet calculated.
The other 3, have zero ability to navigate the world. One has been told he is special since the day he was born and now is failing out of High school because he has zero ability to handle adversity. ( He has a diagnosed disability and willlikely live with his parents his whole life, he seems to think he is smarter than the rest of the world)
22 Y/O maybe has a chance but will likely end up with a miserable life because he has zero ability to stand up for what he wants or thinks. Smart enough to be ok but still lives at home, has been "going to school" for years with no end in sight.
15. I am genuinely concerned about. These young men have ZERO fortitude. He quits playing games against his little sister.