I've heard of that happening with the flu as well; people in dynamite shape get it and pass. I'm not trying to downplay the death of your friend, as I've lost folks to COVID as well. Just noting that it's still very very difficult to know if a mask would have actually saved someone, given so many people (especially healthy people) take very flippant attitudes towards vital measures such as washing hands, properly covering one's mouth when coughing/sneezing, not touching the face...masks don't help with any of that, and we know that most people don't observe said measures very well at all.