If you are carrying a deadly defense weapon, it is your moral duty to avoid confrontations, almost at any cost. You are not a cop, so don't act like one.
This fool confronted a driver because she had parked illegally. Then her "boyfriend," the unmarried father of her children, started a physical fight with the fool. At that point, we have at least two fools. Maybe three.
It is not your job to play parking monitor, nor is it your job to correct someone else's morals. Remember that you are carrying a deadly weapon, and that it should come into play only in an unavoidable emergency. Therefore, it is up to you to avoid confrontation, thereby to avoid creating emergencies.
The "boyfriend" got what he deserved. Now the shooter will get his own comeuppance when the "girlfriend" takes him to civil court seeking damages.
She may not win her case, but it will surely—and appropriately—bankrupt the shooter.