Agreed. Do no further injury to the victim and wait for the pros to get there unless dispatch instructs one to move the injured party.
His neck could be a major problem there.
I would be reluctant to touch him, and would urge others not to as well. I would urge him not to move also.
If he’s unconscious and not breathing, you would have to address that.
Otherwise wait the five-seven minutes for trained people to show up.
Many municipal areas have rescue teams just minutes away.
Seems like an eternity at the time, but it’s best to do no harm as you said.