I’m sure Wanka has a O2 sat. He should have one with a alarm. There are different things that can go on with the lungs including Cytokene storm that won’t show up on a X-ray as pneumonia but without quick intervention is deadly and what probably killed most of the people on the SPANISH ” aka swine flu” out break in WW1 era started by vaccinating the soilders and getting them sick. Your own immune system will Attack your lungs it’s life threatening and deadly. It still goes undiagnosed and out probable pneumonia or some such thing On cause of death. You probably didn’t have that. You could have had a bad case of Bronchitis that wasn’t showing up and turning into pneumonia. Either way you should of been treated and maybe done a sputum culture or in your case with low O2 maybe even a CT scan. You can have pneumonia and no or low temp.
pS Congrats on Grandson.