This case dont sound right to me. Something fishy is going on here.
1. Why didnt he go to his Credit card company first?
2. If someone hacked into his account, usually they would change the password and lock him out.
3. If hacker have control of his account, why not buy more games?
4. Sony would able to track down the console that credit card was used on other than his own.
5. Did he use his credit card on a friend, sister, brother, or family console and they bought a game without his consent. But since he willingly enter his CC info on the console. The Credit card company is not refunding him so he decided to go to Sony?
6. How do we know that he didn't buy the game on his friend or family console himself?
There are a lot of missing information here. The only thing we know is that the game was purchased on another console using his credit card.
If i was a hacker, I would not be that stupid to buy a game on my console with a stolen credit card. Sony can track down the console that it the CC was used on. But if i was a stupid hacker, i would buy as many games as possible using that stolen CC. I would also use that information to purchase other stuff too.