I know a lot of people gave him tons of flak for his cancer decision, and it may not have been the smart or right decision. But having been in the medical line and meeting tons of cancer patients, i can tell you that there is no best decision when you faced a terminal disease, every choice has it's risk.
Chemo is not a fool proof method, a LOT of people dies from chemo. Because chemo is like nuking your body, and crossing your fingers that the most minute cancer cells (which they can't detect) doesn't return, if it returns, then you are f-up, your body is in shambles, it's free real estate for the cancers. Most of them died if this happens.
At the same time, not all cancer kills you immediately. There are people who decides to "fuck it, if I'm gonna die, might as well enjoy life more" and opt for no chemo, and and still live for 15 years later..... with the cancer still in their body. All they did was just taking supplements to keep themselves healthy.
So yeah, maybe he took the wrong decision and died, but when you are faced with the same terminal illness with tons of money yet refusing chemo, you might just understand why someone would choose that path.