You should talk to his pulmonologist about pulmonary rehab . The therapist not only give you ways to increase lung capacity through exercise - and big part is educating you on your lung condition for him COPD - this may give him some peace & give him someplace to talk to professionals who can give him some insight on his condition. Sometimes the not knowing causes anxiety & fear and the need to try to control what he cannot - which is his COPD. Pulmonary rehab would give him a place to express his fears and have professionals help him understand his condition & what he can do to help increase his lung function. He sounds scared & just waiting for things to get worse - education on his condition & what he can do to help strengthen his lungs may help him so I encourage you to talk to his pulmonologist. Take care.