When you're 16-17, and you're taking in £1,500-2,000 a week, it's gonna do ridiculous things to you.
If i was getting that now, i'd probably be a bit tool tbh, you lost sight of a few things when you're younger and when you're 16-17 and have the weight of the world on you, move from your home to a new area and have all this money, I expect it will mess you up. I expect he had a lot of "hangers on", giving him some unhelpful advice.
Mental health is such a big thing, which seemingly many do not understand. Okay, he's acted a bit silly, but full credit for admitting it. That's the first step.