My mum had it for 20 years and never smoked!
Anyway, at this point there is no way of knowing if he will improve ot not. Emphysema is characterised by breathlessness because the lungs are damaged.
Your uncle will be very susceptible to any colds or chest infections, and will need anti-biotics ever time he catches one. He will probably need much longer and stronger corses of them then usual
The disease is managed by regular use of inhalers, and as your uncle stabilises he may find his brethlessness reduced, although it may never go completely. I am suprised they have let him out of hospital TBH, although it isn't really the best place for emphysema sufferers TBH.
Have they started him on a programme of inhalers? This is then usually managed by GP. If he is really bad, they will offer him steroids, but you can't take them regularly.
I am suprised at use of oxygen TBH, it was avoided at all costs my my mums doctors etc.
It generally improves in summer weather.
Best drug that I can remember is an inhaled one called Spiriva, BUT very expensive, and medical profession tend to offer it as last resort because of this. However that is the one he will probably do best on.
HTH