Despite (or maybe because of) all the money he has, he's still just a kid. He thinks he can do whatever he wants and get away with it. Unfortunately, that's not unlike so many other youthful artists who game fame before they gain common sense.
I think when they become so famous at such a young age they have to be "perfect" to protect their image. Then when they get older I feel like the constraints of that lifestyle become too much. Problem is when they rebel they have all the media watching. And all the money in the world to do whatever they want. And there will always be yes people in his life who let him do whatever he wants so they can stay close to him. It's really sad.