What to do about fake Xbox live account?

My little brother - aged 7 - decided it would be a good idea to make a fake Xbox live account. He used a fake name and address but he will not tell me / "he can t remember" if he put in fake card details or anything to pay it with. From what I can see he hasn t but there is a payment option and I m scared he ll use a fake one which will end up being someone s real one. I know I m not making a lot of sense. The account info says it s free but I m not certain. I went to delete the account but he says it has all his work on it, and I d feel bad deleting it. Plus I have a minecraft world on that account. What should I do? Should I delete it and make him hate me or can I deactivate only the Xbox live account and leave the Xbox account with the data on it?

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