He had a much more treatable and slowly growing variety of pancreatic cancer - it was a neuroendocrine cancer in his pancreas (an islet cell tumor). The 5-yr survival rate for stage 1/2 is something like 95%, and even stage 4 is still around a 25%. The more common and deadly pancreatic cancer you’re thinking of has a 5yr survival rate of under 15% and under 3% if it’s advanced to stage 4.

If he had received real care immediately after diagnosis, he’d almost certainly be alive and cancer free today.

I stand corrected!

Not moving goalposts, but on another note:

He refused regular treatment for 9 months, for an allegedly slow-growing type of cancer?

That still doesn't sound that crazy, especially given he lived another 8 years.