I have read a lot about this because I did not want it either. But you can loose a lot of wieght and nutrition from this. I only weigh 145 pounds and have a high matabolism. I can not afford to loose 100 pounds as I have read so many times. I offer two things.
1.) The best thing would be to convince him to stop being so stubborn! He must understand that what he decides also affects the ones close to him. The worry and concerns are different, but they both have an emotional toll.
2.) Assuming he sticks with his original decision, get him to drink Ensure or boost. This is a liquid that you can purchase in any grocery and will give him the nurtients he will loose during treaments.
I buy frozen strawberries and thaw as I need them for the day. Then I blend some in with the ensure in a blender. This takes the awefull vitaman taste away, so that I can drink it. It actually tastes good that way. I buy the 350 calorie one so that I get the most I can from it. VS. the normal 250 calorie one.