He hasn't cheated in a FIDE event as far as FIDE knows. Banning him for cheating at 12 and 16 in an unrelated to them place (and not even OTB) without anything else would just be bizarre. Even more so, when players who have actually cheated in actual FIDE OTB games as adults start off with a temporary rather than permanent ban.
Part of it is that he cheated on Chess.com which does not publicize bannings for cheating/punishments, so there wasn't really a reason for the tournament to not invite him since at that point from an organizers perspective it was just rumors.
People make mistakes. Also, it is kinda difficult to cheat uncaught in over the board games.
Cheating is a character issue. If he admits to cheating at 12 and 16, he’s cheated since then and will again.
That's a frankly ridiculous point of view. You're talking about a literal child cheating at an online video game. It's not that big of a deal, kids do dumb stuff.
I don’t consider 16 year olds to be children. If they are, they shouldn’t be driving. Yes, all kids do dumb things. But, if you are still behaving stupidly or dishonestly at 16, well that’s a different issue. That it’s no big deal to the younger generation explains why the country is as messed up as it is.