I was going to have him regain consciousness in the ambulance on the way to the hospital, but wonder what would the paramedics/EMT (which/who would it be) be doing in the ambulance? What would they do if he “came to”? And what would happen when they reached the hospital?
If he wakes up in the ambulance, they'll first orient him to what happened. "Hey Mike, my name's Roy and I'm a paramedic taking care of you. You took quite a hit on the ice and you were knocked out. To be safe, we put a c-collar on you and put you on a backboard to protect your back. We're on the way to Swedish Medical Center to get you checked out."
Then they'll assess him. Can he move everything? Can he feel everything? Does he know his middle name? Does he know the month? Does he remember any part of the accident? Does he know what city he's in?
The doctor will likely order plain x-rays of his neck and spine and a CT of his head. If all that checks out-- he would probably be discharged home.