I wouldn't be surprised if this kid was groomed online and then used as a patsy to intentionally leak documents they wanted leaked. The leaks are surprisingly weak on damaging information considering all the really shady shit the US has been up to lately. One possibility is the CIA/NSA/feds of some sort caught wind of some dude blathering on discord about having access to secret military shit, quickly figured out who he was, then let him access and encouraged him to spread stuff they wanted him to leak, including possible false Ukraine war stuff they wanted the Russians to believe.

For good measure they were possibly encouraging him to carry out some mass shooting like they did the Buffalo supermarket shooter so it's win/win for them. Leak partially false info they want leaked, use some patsy to convince the Russians it's real, and then try to get him to go out in some insane homicidal spree(or at least make it appear he was "planning" to) to make sure he's not seen as some anti war hero and so they can use it to further crack down on dissent.

No way to know if that's the case, but as I said before a lot of people were suspicious about the leaks from day one and the fact the media so aggressively reported them when they usually ignore or supress bad news or embarrassing shit about Ukraine.