Originally Posted by FngKestrel

Has he played other MMO type games? I find that people who are freshly exposed to something new usually have a hard time regulating their time because it is so new and overwhelming. From what it sounds like, this was his first interaction with MMOs

I've had friends who discovered the joys of making their own website and did so addictively.
I've personally been addicted to MUDs, back in the day when it was just text. Which is why I have severe reservations playing any graphical MMO.

If you want to get him to stop, you'll need a group effort. Like what pan said, get everyone on the same page. Maybe an intervention? Does he understand how much he's hurting everyone? If he can realize that, then maybe he can initiate change to fix things.