When I started chemo, I was given a 'nutrition' guide, that recomended ice cream, candy bars, etc., as if the only thing that mattered was weight. I stuck to the protocol and did not worry about my weight. When you eat high nutrition food, your body will shed excess pounds, no more.
Spend the $$ on qulaity food, a good juicer, and nutritional suppliments. Don't waste them on MLM garbage.
You shoudl check out the Moss report. It will be a great resource for your dad. I bought one for colon cancer when I was early in my fight.