It’s the violent nature his dad whacked the poor dog with that I object to. Surely the dog didn’t bite his dad out of the blue. There are a lot of unanswered questions:
Was the dog owned by the dog’s life ender
Was the dog a stray
Did the dog (which was lying down in some vehicle) get up before he bit the person’s dad
Was the dog already injured and perhaps that is why the dog bit
Is it customary to whack a dog in the head to kill it in this person’s neck of the woods? Especially a lying down perhaps already injured dog
What was the dog doing in the vehicle? How did he get there? Did the dog’s life ender put him there? Why?
And so on
I would have done what tet68's dad did.