Could be. I thought he said something about lungs. Colon cancer metastisizes mostly to the liver and lungs. Although the chemo is basically toxic too. (I hate it) But if the cancer spread to his lungs that could have been the problem. But they have very good palative care, to ease the pain. And sometimes its better to go quickly.
How well I know. My dear Dad died when he was 42 and I was 16. 6’2” = 85 lb. skeleton at death. Many years ago, of course, but I still have huge mixed feelings about the poisonous drugs that are used. I think they may kill all the body’s natural fighting resources.