Just internet speculation because there were two sets of shots fired. The car was fired upon, by someone with a handgun on the crowd. If the guy with the AK fired, it probably would have been more clear on the video.
Moot point, he pointed the gun at the driver and got what was coming to him.
Anyone who has a gun pointed at in has the absolute right to act as if the gun SHALL be fired. So yeah, bottom line the person in the car acted in justified self defense.