Dehumanizing staff in front of customers

I went to the Santa Monica spur in muizenberg cape town and I had to go the extra mile to air my complain, I was having dinner with my family and the manager of the store was swearing at two of his waiter it was so dehumanizing and is not the way to speak to employees in such a disgusting manager my wife wanted to cry just watching that, I had a word with him, something needs to be done you cannot do something like that in front of customers the food was terrible and to top compared to the spur I normally go to. He is a short stocky male manager.