He should pay the tax he owes his government if he doesn’t want to relocate. It’s really that simple, unless he’s willing to risk a lot of trouble with the tax authorities.
Everyone talking about you can't run, tax fraud and all that. His income is 5k USD. I have a hard time believing any tax authority is going to hunt him down for such a small amount, except if he relocates to one of the Scandinavian countries.