12 month old wakes in middle of night coughing. What is going on?!!!?

If he was littler, I would be worried, but honestly? I think he's faking. He's found something that has you running to him in the middle of the night & he is old enough to know how to use that to his advantage. If you are concerned, call his doctor. But I really think this is a clever tactic to get you to pick him up.