I'll add more detail now. Just wanted to get that first post out there. Yes a small amount of coffee will be fine for him(obvisiously not hot though). No milk products, that will make it worse. Do you have any Vicks Vapor Rub?? Try putting it on the tops of his feet. If he continues to wheeze and breathing seems labored, I would take him in to er if you can. They can give him a breathing treatment there and some steroids which will knock it out. Keep him upright, it helps with any drainage.
My brother had severe asthma growing up...Try giving him coffee, or anything with caffeine. It helps open up the lungs. Coffee is best though