COPD is an epidemic and one that really sneaks up on you...woke up one day and couldn't breath. I've been dealing with the worst of it these last 6 years & your right, it's not so much the body being able to get enough O2 but also ones body being able to get rid of the CO2 -- it stays stuck in the blood & leads to organ failure. My Pulmonologist has me on high doses of Prednisone every day, so I've gained 100# & fractured 6 ribs & a vertibrae & bone scans say I'm high risk to break a hip...thanx Prednisone. Also 3 different nebulizer chemicals, also steroids. He prescribed me the BiPAP but I couldn't do their sleep study -- too uncomfortable, so insurance wouldn't pay for it, so I bought my own & am on BiPAP about 12hrs/day.... I also have the High Output O2 concentrator, but use air tanks for travel. Fun fact, I used to smoke when I was using them & lit myself on fire twice. It was absolutely insane craze fire, like from a jet engine, except up my nose & face....stopped doing that. I also take Daliresp and Spireva. I'm mad at myself, especially when I see all the tree work I used to love doing so much. Did this to myself.
I'm sorry you lost your wife. That's very sad.