The temporay IP ban you got is an automated feature that triggers when you get a password wrong 3+ times (that's when you get the message "wrong user ID or password"), regardless on which account you get it on, this is related to your ip, the temp ban lasts 10 minutes.
Now about your nephew's account, if he is the owner of the account (the one who's email is on it), then he should do a Password Reset via the CP:
http://www.pandoraonline.net/cp/?module=...=resetpass
Unless someone has access to his email or his computer he should be safe after that, but to be extra sure he could also create a new account under another email and restart fresh, he only has low level novices on the account so it wouldn't be much loss.
