you're an idiot, if his car is only over heating when he is stopped, his fan is not turning on. if his thermostat was getting stuck it would over heat at other times as well. He can either buy a new fan if his is broken, or run a switch to the fan, or wire the fan to come on with the engine, all of those will fix the problem, which is what he wanted, theres nothing wrong with any of them.
Op, if you're worried that it is not only your fan, replace your thermostat since it is extremely cheap and easy to do, check your radiator, feel for cold spots, that way you know if theres any type of blockage, do a coolant flush as well, which is easy and cheap, and once you're done with all these processes including fixing the fan you'll have the piece of mind that your cooling system is running properly