Can Dogs Get Traumatized From Negative Punishment + Electric Shocks?

My dad doesnt believe he's previous dog was traumatized even though he told me stories of how his grandfather smacked the dog for doing wrong things, (eg. if the dog poo'd in the wrong place, he would rubb the faces face in it and then smack it). He defends hes grandfathers actions by saying he was the best dog ever and never showed any signs of being traumatized. Now with my dog he wants to use the eletric collar on him when he does his business in the wrong place and i told him positive reinforcement is better than negative reinforcement. Whats your ideas?