Hello Susie
Like your husband and Gary, I lost a huge amount of weight. I had the same treatment as your husband with no feeding tube. Whatever I ate didn't seem to affect my weight initially but 27 months after I have regained much that I lost.
Your husbands blood will have been affected by radiation and that also will make him weak.
I assume that he is having Hospital Sustagen with fibre (or similar) every day to keep up his nutrients. I still have it now because my diet is restricted owing to lack of saliva.
The American Cancer Society web site has recipe suggestions to tempt patients and help increase nutrient intake. I found it very helpful.
Your husbands recovery is very similar to mine and I am now doing fine.
Best wishes to you both, love from Helen