He needn't tell them he's jobless. They are too lazy to check, anyways. He can 'invent' a job on his cv. But you're right about them taking advantage if they knew about him being out of work back home.
Though China is unsuitable for real professors as a rule as regards satisfying employment, it's a good alternative employment-wise for Mr Average who's been twiddling his thumbs out of work in his homeland. You see, everything is relative. That said, it's a fact that many Westerners find it hard to adjust to the different culture here, but I'd imagine that folk out of work back home for long periods would have fewer problems adjusting to that and the inevitable boredom here. I reckon that lazy folk might be very well-suited to teaching oral at an average senior high school over here. Western losers can acquire an elevated, though undeserved, status here on account of their Western looks, especially out in the sticks, where they are thin on the ground.