This is very sad news to hear... I watch his channel occasionally, and I know he's been fighting with cancer for a while now. Very unfortunate that it will end this way in a few years.
I've had relatives who passed away from cancer. It's always a hard thing to deal with.
Make sure to eat your veggies, and get lots of Antioxidants. A class of red wine with your dinner, some coffee during the day.
(coffee drinkers have drastically lower chances to get many types of cancer's)
Dont let yourselv become obese, do some exercise every now and then.
Dont smoke... its about all you can do.
I know its not just smokers that get it, or people that eat unhealthy but.... doesnt hurt to do all you can.