Sorry I can't be of more help.
There are two types of sleep apnea: obstructive (most common) and central (less common and not treated with CPAP, I believe). That is the basis of my concern about discussion with the doctor on the CPAP. In any case, I am not arguing with anything your doctor has prescribed, and sadly I have no knowledge on narcolepsy to share.
Sorry I can't help, but I wonder why the doctor(s) handling the sleep apna having given you a path forward. I understand the CPAP is a big help for obstructive sleep apnea but do not have any experience with narcoleptic - is that the reason for the CPAP?
Hope others can be more help, but your doctors have to be your source of an answer.