The only reason his family was at risk was because he stopped and exited the vehicle to confront the other guys. I’ve driven over a half million miles in the last 33 years and have never and will never stop my car to avoid or confront an aggressive driver. Actually, I can think of only one valid reason to stop. That would be to let the other driver exit his vehicle and approach - giving me a chance to take off with a head start. The shooter’s family was in the car. He was looking for a confrontation. (IMHO)
The only reason to stop is to confront the other guy.
IOW, it’s the equivalent of “taking it outside.” An irresponsible thing to do anytime, with family in the car it’s beyond irresponsible.
That said, there is nowhere near enough info in this story to assign responsibility.