When I had COVID in January of ‘21, my sister said I should sleep on my stomach. I did not follow that advice because I know my breathing is even more restricted on my tummy than on my back. My lungs, thankfully, never filled with fluid but the advice didn’t pass the smell test to me.
Either she didn’t hear the “on a ventilator” part or she was watching CNN and was intentionally misinformed.
My wife has copd/emphesyma and must sleep with oxygen and on a constant o2 monitor while sleeping.. There is a 3 to 5% O2 saturation increase when she sleeps on her stomach. Difference between sleeping at 93-94% vs 97-98% saturation.
She can be sleeping on side or back at low 90's saturation or below and when she repositions to her stomach or at least 75% to the stomach it will rise to 96-98 within a few minutes, every time.