Becoming compliant isn't a paperwork task. It's going to be expensive. He hasn't been withholding any taxes; he could end up owing as much as $1000 for each prior month he failed to do that.

The city and state his business is headquartered in (he's in DC Metro so it could be any of a bunch) is also going to tear into him for unemployment taxes and fees. We had drama with this even though we don't even have independent contractors.