Coincidentally, Michael's tongue was said to be cancerous due to too much cunnilingus.

If he had a swollen tongue it wouldn't change the pitch of his voice. I always heard some wheezing when he was talking. Either he has an infection like pneumonia or a cold or cancer and I doubt it is an infection because this has been going on a long time.

MArley was a sort of different story-his religion didn't prevent him seeking treatment- he just decided to go seek help from holistic therapists, and others. The doctor's suggested amputation of the toe where the melanoma had begun, he instead had the toe nail removed, as well as the nail bed. And he went with a 'cancer' beating diet-which did nothing, tbh.
Similar to what Peter Sellers did when he had heart trouble (ie heart attacks).
I suspect that some time in the 70's, more and more of these 'we can cure you without poisons' movements sprang up(Scientology first gained major prominence round that time, especially targeting celebrities. Just giving a context and example). And that was why so many didn't take doctor's advice, and lost their lives to the disease.

Maybe but I think he just wants to keep it private. Bob Marley died because his religion prevented him from getting treatment which eventually killed him.
You think a few bolts of cloth will make you king?