An additional information your friend might benefit from, no guarantees:

This is likely a very good and important information for people suffering from Cystic Fibrosis, I think one should take this Dr. Artour Rakhimov very seriously, see
https://normalbreathing.com
and see his book
https://www.amazon.com/Cystic-Fibrosis-Life-Expectancy-Childrens-ebook/dp/B00793UMNQ/
All this is based on the extensive research activities by Dr. Buteyko (in the 1960s already) during the soviet space program, aka "hard science" (or "real science", if you will)!

Oh and combining this method with the oil-protein-diet by Dr. Johanna Budwig is most likely extremely recommendable for a long list of reasons, so you might try this too, please do your own research! Both methods work together very harmonically, as both are focused on improving O2 supply for the body.

Also incline your bed see https://inclinedbedtherapy.com as this is supposed to improve lung function.
#cysticfibrosis
#cysticfibrosiscure
#curecysticfibrosis