jobo
Grandmaster
well you didn't see anything that's says he can't.Have you ever done Jiu Jitsu? Because you can learn the techniques fine and easy and drill them in class but literally everyone says when you get to free rolling it's way way harder to pull off. In most places you get a stripe when you can hold your own in rolling and win a few rolls. Most people it takes at the very least 4 months to get a stripe and I didn't see anything in that video that showed the kid was capable of holding his own against a white belt
if you look at the video of the attack, a kid much smaller than him beats him up whilst he makes no attempt at all to defend himself.
people are bullied not because they can't fight back, but because they don't, , now after say twenty hours of training he is in a position to know he can fight back, its that psychological shift that's most important rather than the,actual skills learnt.