Do Hearing Aids Have Volume Controls?

Does anyone know if hearing aids come with volume controls?

Today noticeably cranky, elderly man and his wife came into the restaurant. I got them as good of a deal as I possibly could on the food that they wanted. When I delivered the food to their table the man demanded (in a louder voice than he used to order his food), "Can you turn that d--- music down!"

The jukebox was already on low setting but I turned it down anyway (now pretty much no one in the store can even hear it). The man later came back up and accused me of 'being kind of screwy' with the price of his food. When I explained how I gave him a better deal by combining his food into a combo meal he walked away in disgust muttering, "Don't know how you want me back with these prices and the loud music."

There was nothing I could do but secretly laugh and pray the Lord takes me home before I'm 80.