I know you hate to see your husband losing weight. You feel helpless as you watch him go through this huge life challenge. From a cancer patient’s perspective, I think the caregiver may have the rougher time adapting to the new situation. As a cancer patient, we just try to get through each day with whatever happens. Our lives have changed abruptly and our personal focus has pretty much blocked out any other thoughts. Unwillingly, we become the center of everyone’s attention!

The caregiver, not so much! You are being thrust into a position of having to take over the other person’s role while they are incapacitated to varying degrees. Your life changed drastically too. But instead of lying in a bed or lounging on a sofa in fight or recovery mode, you are flying by the seat of your pants trying to keep track of everything, including items that were taken care of by your partner in the usual division of labor that comes with marriage or having a close significant other. You don’t get down time! You’re filled with worry, stress, med lists, appointment calendars, making sure your husband eats, all while trying to balance everything else.
It’s good to keep a diary of your husband’s weight so that you can bring it up with his doctors. His eating will return slowly. I did find a couple of discussions over several groups regarding chemo and not wanting to eat. This is one you could skim through for ideas of food.

When will food taste good again after chemo and radiation? https://connect.mayoclinic.org/discussion/trying-to-get-food-into-husband-after-chemo-and-radiation/

Try the little portions of food I suggested. Think bite-sized and not pieces on a plate. I would give my husband ideas of what I ‘might’ be hungry for and maybe could get down…but usually I could only gag down a bite or two and then I felt bad for all the work he would do in vain. Eventually, I was able to eat more and my appetite gradually returned. Your husband will too! In the meantime, he may lose more weight but it’s not your fault, ok? Unfortunately, those pounds are collateral damage in his fight against cancer but they should return when treatment is over. ☺️