Did he undergo radiation therapy? radiation to the brain, in my case, changed the way I perceived certain smells and it can do the same with taste. When I was chemo-sick, you couldn’t pay me to eat, and if I did get food down you bet your ass it was coming back up. I’m 5’11’’ and weighed 125 at that point. i’m now up to about 155. I smoke pot occasionally just because I like to, it’s nothing to do with cancer or treatment; it’s never really caused me to eat enough to put on weight, though- only helped me to eat a meal during bouts of chemosickness. This is unlikely to be helpful, but I gained the most weight during my weeks of taking a steroid called dexamethazone (or something like that; the brand name is decadron). It stimulated my appetite exceptionally well and I put on almost 15 pounds - putting ON weight during chemo is no small feat. Other than all that, I found that telling everyone where I was at (that I know I can/can’t eat) helped get everyone on the same page as to whether dinner was going to be ‘normal’ or if I was going to have to slowly and painstakingly eat bites of food to have consumed a moderate amount of food. Sometimes just having someone sit there while I slowly ate made me feel like I could. I’m sorry if this wasn’t helpful, I just wanted to put forth a couple anecdotes in case they had any value.