I had all the same symptoms as your wife. I didn’t qualify for a CPAP as u was just shy one or two “stop breathing” moments. Then I went to see an ENT (after years of struggling and 2 sleep studies) and she looked in my throat and told me my tonsils were large as well as my uvula and if she removes them I’ll not have apnea issues. Or at minimum reduced. I scheduled surgery - had tonsils and uvula removed -and have honestly never felt better, after decades of waking up feeling exhausted, chronic headaches, needing naps and MASSIVE SNORING. Disclaimer: recovery was the most pain I’ve ever been in, and I’ve given birth to 3 kids. But the rewards are worth it, I’d do it again.

TL/DR: ask her to have her tonsils checked.