Anyone who is incapable of handling any firearm with absolute safety does not under any circumstances deserve to own or use a firearm. "A neighbor, Thomas B. Jadlowski, thought he saw a deer in his back yard 200 yards away and fired a single shot. Then he heard a scream." ("He thought he saw a deer and fired his pistol. Now his neighbor is dead.", Washington Post, 11/24/2017)
I don't care that the shooter called for help and rendered first aid. That was the absolute minimum he had to do once he, the shooter, took matters in his own hands and deliberately loaded a handgun, pointed it at an unidentified target and pulled the trigger.