Believe me the introduction of CPAP into this person's life was a f*ing disaster for her and everyone who was around her that year! She went to see ~11 doctors, finally quit the CPAP on her own, without any doctor's suggestion. Things got better immediately. Then out of desperation she went to a Chinese herbal doctor. Somehow after that the cough began to die down. I make no claims for Chinese herbal cures - I'm amazed anything worked after that year.
While apnea is real, CPAP looks like a scam to me, for the sleep clinics and especially for the CPAP makers and suppliers.