It is. He claims that with a specific seed, he's done it in much less (4 minutes maybe? I don't know). It's possible his speed-run record with a random seed is 14 minutes now, but I'm not entirely sure about that.
Last year, his class at school (he was 12-13) had their own server where they built lots of stuff. At some point, they divided into two teams. His team was the largest, which he found unfair, so he switched to the smaller team. Then both teams secretly decided to gang up on him, which they did when he wasn't prepared. 20 kids, against him on his own, without his armor on. He had an enchanted golden apple ready, quickly put on his netherite gear, and went to town. Beat them all.
As part of a special projects week the school organised not just a regular sports day, but also an e-sports day. 7 events. He won 6 of them, including one game he'd never played, and got silver on the one game he didn't win.
He's ridiculously good, that much is clear to me now. I'll let him know the internet says he should get a Youtube channel. He doesn't talk much, though, and I think that's kinda necessary for a youtube channel.
