There's no reason to suggest that this guy is over aggressive in disciplining his dog. The dog was probably incredibly timid and easily spooked before it ran away. After all, it did hop a fence and run away simply from experiencing fireworks. That's quite a powerful experience for most dogs, but it generally doesn't send them running away wildly. My guess is this was a very timid dog to begin with, and the owner didn't spend enough time socializing the dog to help with that problem. A lot of working dogs are prone to being timid like that, and this dog looks like some kind of shepherd mix.
That said, even though the dog approached in a very timid and submissive manner, it walked right up to the owner without hesitation. It was clearly familiar with his scent. It took the dog a little while to fully grasp what was going on, but you could definitely see the dog loosening up in just a few seconds, and it was clearly quite happy at the end of the video.