Perhaps COPD would be affected the same way asthma would. Our family had been living at high elevation in a semi-arid country. When we took a trip to New Delhi (hot, humid, low-lying) my young son had trouble breathing and was diagnosed with asthma. We returned to our mountain aerie and the asthma disappeared. He went with a young friend to Israel (hot, humid, low-lying) and the asthma returned. I have COPD and suffer on humid summer days. Whether this is due emphysema as well as asthma I do not know.
Humidity and heat is hard on me as well, but cold is just as bad. Try to stay in air conditioning as much as possible when the humidity is up, but make sure she gets exercise. Walk and walk and walk somemore...