He's really, really lucky there were trained professionals on hand, and that hitting his head meant he didn't have to subjectively experience any of it. (I stayed mysteriously unresponsive. “General appearance: comfortable, in no distress.”)
For medical providers, working on a dying person is itself traumatic. Doing so on the spur of the moment in a hockey game would be doubly so: you're just trying to relax and enjoy yourself, but all of a sudden you're on; then you feel you have to be ready at any time, and can't relax.
Then going back to hockey might sound heroic, but it really puts the EMT and paramedic in a tough spot, having to relive it and also worry about having to take care of patients who risk their lives without regard to their impact on others.
This is well-written, honest, with the essential facts to be a good contribution as an anecdote. I do thank the author and wish him well. He has friends everywhere now.