My dad had emphysema for years and a couple years before he passed away he was on oxygen. So that meant no open flames in the house. He was extremely sensitive to smells. We had to get rid of our dog cause of the pet dander and smell. Even before the oxygen, candles would sometimes be a problem if they were highly scented. It would shut his breathing down even worse than it already was. I was a teenager so I didn't make candles then of course. We usually had to wait till we were in the car to even spray our perfumes. Maybe his wife's COPD is not as severe but I don't really understand why he would want to take the chance?? If they are just wanting candles maybe you could make unscented ones? I didn't know if he is really wanting something scented or just the ambience of a burning candle?