Pat, I forgot to add that I hope that your son is doing OK. My dogs love to bark at our mailman but our yard is fenced in and they are normally in the house. They bark at anyone that comes to the door. The UPS man is afraid of them. He always tells me, don't let them out! They haven't ever bit anyone.
We had a lady mail person that always left a doggie biscuit in the mail box for them. And if she would see them out back she would stop her truck, toss them a biscuit and talk to them. She was a wonderful mail person, she went out of her way to help people. If she knew you were sick or unable to go to the mailbox, she would bring it to the door.
Hope your son doesn't have anymore scares! Or dog bites!