Is it really asthma?

My husband was finally diagnosed with pulmonary fibrosis 10 years ago.(It took three years for them to give him a breathing test - they told him he had no air - we'd known it but they just kept saying it was a sinus infection)  HE had a lung biopsy.  The doctors always thought his lungs sounded good and he never had a dry cough or wheezing. BUT he's ALWAYS has coughed up lots of clear phlem. He got really bad just a year and a half ago. The Dr gave him a large double dose of ashma medicine and he felt great, but they also gave him a good dose of predisone for 4 weeks and started him on a nebulizer.  Got the flu in December his lung went down to 80.  He's been on  oxygen 24 -7 since but still has the terrible cough with phlem, he had lots of side effects from Advair.  The Dr says his lungs sound great, a cat scan show the same but he has no air and pants all the time. He's in big trouble if he doesn't have his oxygen on and walks a little bit or forgets to put it on at night.(He was hardly using hi oxygen before the flu) He got the scaring from spraying weeds on a job he did for several years.  Something isn't right but our lung Dr has no ideas - he says he never knows what to do with him. (Just come back in 4 months - I'm the one who figured out he was having the side effects from Advair.  The Dr wasn't pleased with me.)  Do you have any ideas?

[National Jewish]

You state "The Dr says his lungs sound great, a cat scan show the same