I'm not sure if you will find this helpful or not. My truck does not have a manual choke. For cold starts, I pump the gas pedal twice then start the truck. Then it's a matter of waiting a few minutes as the engine warms and increases idle speed. Once the engine evens out, I tap the pedal and it bumps the idle back down. The first time someone experiences this (my roommate wanted to borrow the truck and caming running inside in a panic) it can be loud and scary as the engine revs up.
By the way, can your son please send the cold weather back? It's looking like May up here.