You can make yourself crazy by worrying about all of the possible causes for those things that we would all prefer to stay clear of: cancers, alzheimer's, parkinson's, whatever. As a reformed smoker, I'm particularly leery of inhalable stuff: particulates (looking at my blasting cabinet), fumes (looking at my MIG welder), and can't-see-it stuff (looking at the isocyanate-catalyzed paint that I bought but now won't use). All of us car-hobby people get careless from time to time, and we will never be able to be quite sure whether, for example, that time when we blew out a brake caliper with compressed air was the culprit.
And then there all of the other unknowns. Like airborne virus transmissions in public building ventilation systems. Or the asymptomatic carrier sitting across the aisle on the bus. Or radon gas in your basement. Or driving in city traffic.
Life is dangerous. But all we can do is take reasonable precautions. Otherwise, it gets silly and you spend all your time worrying.
Unfortunately, life is unpredictable, too. We all need to remind ourselves to make the most of our time. A little creating-and-restoring-and-improving in the garage or workshop is part of that for most of us here, of course.
I hope lots more members reach out to our friend, Mark / NorthernZ, even if it's just with a few words of support. Hang in there, buddy. We're all pulling for you.