Quote Originally Posted by Breakbeat View Post
I'm sure you could use a VPN and change your location to Japan (or any region you want), then purchase and subscribe to the game. I doubt you'd even need to keep the VPN on to play, since you can select any data center you want with any regional version, which means you could probably get away with a free/trial VPN or, at most, have to pay for a single month or some extra data, which should be less than US$5.

The only stumbling block would be account creation, if your friend doesn't already have one from when they lived in Japan. Account creation's gonna need a real address and postal code, which you could make up (I do this all the time for foreign TV streaming), but it seriously restricts any future customer service you might need.
That's one way but he doesn't want to risk his Steam account getting banned, especially since he's going to need to do it multiple times every time he wants to buy subs and expansion.