Stand your ground doesn’t allow you to follow someone then get out of your car and shoot them.
As long as you didn't provoke or invite the conflict, you have no duty to retreat from a life-threatening conflict. Legally you may stand your ground and kill the aggressor. (State v. Helm, 209 P.2d 187 (1990))In this case it is clear from the pictures and the audio track being played over and over that they boy was not the aggressor and that he was the one begging for help.
This clown could end up setting back gun rights but it the meanwhile he is bringing the race-pimp circus to town and damned if they don't have a reason this time.