I don't think the guy "has difficulties", I think he's just a foreigner. It's down to the way he chooses to transact business - if he refuses to leave he's more in the wrong than the skank is for not providing services, but if the heavies actually threaten or assault him (rather than just the implication of it) then they are more at fault than him as they should call the police. But it's not clear that they actually did, so I would say he only has recourse to a civil court, which in this line of business is ludicrous, so he probably hasn't got a leg to stand on legally speaking.