He put in bank information, assuming that he would be getting +$$$, which looks like and uses the same system (or similar enough if you're 12) as the method for -$$$.
I'm not shocked a 12 year old, dreaming of easy internet monetization, didn't pore over the fine print.
> [family says] the company (Google) only asked for a bank account number and a name, without any more requisites. . .The account was already in red numbers when the bank called the parents to alert them.