Got your letter and was pleased to learn all that occurred. You have a wonderful spirit that shows as well in your writing as in person.
I do not like the idea the anyone, especially K--- who is your love and husband, who uses a CPAP unless they are at least learning how to breathe in the hopes of getting off it some day. I believe it forces an unnatural preset breathing rhythm not related to the ebbs and flows of one's moment to moment energy changes and that that is not good in the long run. Though it certainly can be good in the short run for sleeping for many.
I started to snore and feel borderline apneac in that I could not relax without "coming to" with a "start" having not breathed enough. I Transferred to a very hard massage table sleeping surface, a large pillow under my knees so I would stay on my back in a ribs-up position all night ( I train people to do that) with a small thoracic pillow . I also began swimming the breast stroke. In a week the snoring and apneac stuff went away to stay away.
I suspect that the position of the rib cage needs to be high so that the diaphragm can rise easily and if the bed is even slightly soft the body sinks down and inhibits effortless diaphragm rise (excursion) often enough that it gets used to staying down there at the bottom of the cycle. Sitting at a computer exacerbates the situation. As great as it can be , too much of Tai Chi and Chi Kung is in partial flexion with out the ribs being up like a singer's. Or there is not enough emphasis from the teacher in the extension positions.
The breathing coordination system needs to be used more with the body in extension, hence https://breathing.com/pages/shortness-of-breath
Stay well and the great person you and God have guided yourself to be. My best to your beautiful family.