Self help helps.

I have been prescribed for un-named lung problems since 2005. I say un-named because it was many years later that someone referred to it as being COPD and sent me on a rehab course.

Pulmonary Rehab

Firstly, in rehab they teach you exercises - if you are new continue them for life and slowly try to make them harder - it will make your lungs work better.
After almost continuous exacerbations being "cured" with antibiotics and steroids for several years it seemed to me that that was to continue until the grim reaper arrived - not a nice thought.

Immune System

I took the view that if I got the flu or a cut went septic my body's own immune system would jump into action and hopefully defeat the invader (except that antibiotics and steroids act to reduce the immune ability. After an evening's work over two years ago I settled on an old recipe (using foods from the shelves of my local supermarket) said to strengthen the immune system.
If anyone else wants to try this, be very careful and investigate every individual ingredient (I use 4); like onions, if taken in grossly excessive quantities then one ingredient is potentially poisonous. Another, in some unexplained manner, is said to be used to help slimmers but again that needs far larger quantities - it hasn't done anything for my weight.
I had a very minor period of getting puffed and having excess a few months back which suggests that the honey etc combined with unchanged prescriptions works.
Because of the side effects, I have been asked by another body not to disclose the recipe!!!