No, he didn't. He immediately went into the fencing response, a decorticate posturing that signifies brain damage. The reflex that triggers that wouldn't have gone through if the spine had been severed. So even if they had managed to stabilize him and get his body functioning, it's very possible he had already suffered severe brain damage from the shockwave sent through his bloodstream.
You'll see boxers who take a knockout punch do this too but that's usually temporary.
He was effectively dead the instant the bullet hit.
Not a doctor and could be completely wrong, am basing this on other people's analysis.