I dunno about trivial, those guys appeared ready to put him in the hospital if they could. Pretty serious punks if you ask me. But because he started it, and then wouldn't let it go, he's to blame. You can't write a check your butt can't cash and then expect Papa Glock to bail you out.
The thing is, if he hadn't gone after them again, there probably would be no charges filed. He started a fight, got his ass kicked, so far so good. Then the punks he was confronting escalated and started doing serious damage to him - seeing a present threat, his wife drew a weapon, they backed off, and again all good, I doubt there'd be any legal trouble (maybe there would, this is NC and I don't know what the cops are like there). But once he took that firearm and brandished it himself, at guys that were retreating, and then fired it... that's assault, much worse than their assault on him.
I haven't seen if it's been reported, but I'm wondering if this clown had his CC permit or was just a joker with a gun in his truck.