And once he pops the head off I’d be surprised if head work were all it needed. If a used engine isn’t a viable option my recommendation is sell it for what he can and buy something else. The plus on the used engine is he at least knows what he’s got with the rest of the car.Well if the cost of getting it done exceeds the value of the car, its not worth doing. Sell it for what you can get and pick up something new (er).
Repair/replacing a cylinder head should be worth doing, but it sounds like replacing the engine is really only cost effective if you do it yourself.