OK, I agree that the whole weight loss aspect could be due to an unfortunate cancer recurrence, however I can posit a chain of events that actually makes sense to me AND includes the "hormone" aspect from the recent email.
1) He had pancreatic cancer.
2) Standard treatment would likely include removal of part or all of the pancreas, probable removal of the gall bladder, possible removal of some small bowel, and almost certainly radiation therapy.
3) Radiation therapy can cause scarring/strictures of the small bowel and abnormal motility, in addition to decreased absorption of food. If small bowel was removed at the original surgery or subsequent surgeries, it would cause decreased absorption of nutrients.
4) The pancreas secretes enzymes that aid in digestion AND absorption-related hormones such as insulin, glucagon. Also: bicarb for neutralizing the stomach acid. Many people who have bad or removed pancreases have to take oral enzymes with meals to break down food. Diabetics have to take insulin to improve uptake of glucose.
5) Loss of gallbladder can cause mild to significant absorption problems.
Add it all up: He might well be cancer-free but suffering from nutritional problems due to his surgery and radiation therapy. I'm inclined (having worked at cancer hospitals) to cut the man some slack.
