The kid clearly knew what was up and the father is just an idiot. I mean, he's letting his child play Call of Duty, doesn't give a shit that the kid clearly plays the games all day and only takes notice when his bank account comes up short. Class-fucking-act parenting, right there.
Microsoft has a system for this and parents never use it. It's their own damn fault if they give their child their credit card and don't teach them about fiscal responsibility. When you make a purchase, the amount it costs is clearly stated, because otherwise they'd be fighting this battle a whole bunch.
Normally, I enjoy seeing huge publishers getting taken down a peg, but I hope Microsoft doesn't give this guy a dime. Or a euro. Whatever. Ignorance should not be refunded. Bad parenting even less so.