In my opinion, it's not about whether it is possible or not, but how a minor can gamble on a gambling site, how he can gamble without the casino knowing that he is still underage, so while many people don't like KYC, KYC can also be done to reduce the use of gambling sites by underage children.
The gambling site has no obligation to return the money unless they have their own considerations to prevent the child from committing other stupid acts, but what I am curious about is how much school money did he use? I think it's not big and according to the story he gambled to get more money to solve other problems, I suspect there was a debt and it could be because of gambling, if true, it's quite sad to see what he is facing.