Jace, my Palomino has the heaves but never coughs any more, I give him a little "Cough Free" every day and it sure works, I would do a commercial for them!
I am an avid reader of Joe camp's books and when Jace and I did the Join-Up he came over to me and sniffed and licked me all over, I was patting and scratching him (he seemed almost hypnbotized by it) and then he sneezed 6 times, shook his head and went to his special Scratchy tree that I trimmed for him and scratched himself more.
When I pat him and scratch him and really make contact with him he sneezes then too. Not every day or every week. Is he just happy???