Concerts should be as inclusive as possible. If that means people can only go if there are seats, then it’s perfectly reasonable that there should be seats.
Wtf are the kid’s parents doing? Like, how does a 6 year old smuggle a loaded weapon out of the house? And why would they even have that in the house? (I know it’s in the US, that last question was more of a rethorical one.)
The main problem imo is that he’s surrounded by yes-men who probably also somehow make money off of his behaviour. His self destructive tendencies are already quite dangerous to everyone around him, but it’s even more dangerous if everyone in your personal sphere affirms this behaviour. At some point you’ll start to believe that you’re in the right.
He needs good therapy and meds, but maybe it’s already too late for that if he’s not willing to accept help.