I have a paralyzed diaphragm and one functioning lung. I'm coping pretty well and am trying to avoid having diaphragm plication surgery, which two thoracic surgeons recommend I do. I try to remember to practice pursed lip breathing to reduce the excess amount of CO2 in my bloodstream, which is causing anxiety. James Nestor wrote a wonderful book called Breath with some helpful information about excess CO2. I don't know enough the excess CO2 issue to know if this would help your husband, but it's simple to do. I also use a hand held plastic things called The Breather, which I got from PN Medical, for respiratory therapy on my own. I think PN Medical actually did some studies with Mayo about the efficacy of using it.