If he doesn't drink anything, he is going to get dehydrated and land in the hospital anyway. He should be getting at least 2000+ calories a day. He can do this on Ensure Plus, Carnation VHC or whatever. It doesn't have to be food, per se. I didn't have a peg and lived on Ensure Plus and water for several weeks. If the chemo is really making him that sick, he can probably skip the chemo or change to a less toxic one, but he really needs to finish all his radiation treatments. He also needs the blood clot addressed as you already know. It's a three day weekend coming up. I'd call his doctors and let them know what is going on with clot and no food/water and ask them what to do.

Take care,
Eileen