Sadly when he was 14 would have been the best time to interviend. He was too comfortable and had too much free time on his hands. You would have had to cut his internet entirely and likely send him to some military type school to get away from his female family members and learn hard work.

He's screwed now. The best thing to do is let him live on his own for a long time and don't help him out unless he has changed entirely for a long time. When he has to actually focus on surviving instead of playing games and masturbating is when he will begin his journey. There's not much else you can do since he is an independent grown man now. Just don't baby him and if he needs money then don't give him any unless he sold his gaming rig first, he can apply to jobs at the library or through a cheap laptop etc.