LIST OF FOODS

We are living in a time when medical science is rapidly advancing in the war against cancer. Your husband has an excellent fighting chance, so fight.

From https://www.verywell.com/energy-density-in-foods-2506872

High Energy Density Foods
Energy-dense foods include sweets, deep-fried foods, French fries, pasta, starchy vegetables, thick sauces, cheese, nuts and seeds. Not all energy-dense foods are bad for you -- but you need to watch your portion size when you eat them.

Some foods, like soups and beverages, can have high or low energy density.

Broth-based soups with vegetables typically have low energy density while creamed soups are energy-dense. Non-fat milk is less energy-dense than regular milk, and diet soda is less energy-dense than a sugary soft drink.

My father-in-law was recently diagnosed and has been undergoing chemo and radio therapies. He lost weight during this treatment and our experience was that he was not keen to eat the typical "three meals a day" and resorted to grazing and snacking on whatever he felt like.

Preparing foods in advance was pointless because there was a high likelihood that he would not feel like that food over the next few days.

To counteract this, we attempted to up the calories of anything that he felt like eating. He would often ask for toasted crumpets, to which we'd slather on masses of butter and jam. Similar, if he felt like ice cream (which he did a few times) we would ensure that it was a full cream version.

A couple of times he asked for mashed potatoes and sausages - I made these with loads of butter and added cream to the potatoes. The sausages were the best quality I could find and I made onion gravy with the cooking juices from the sausages.

I think that in your circumstances calories are king and you can take a back seat on what might be a "balanced/healthy" meal plan*. If he likes cheese, nut butters, nuts, bacon, or steaks I'd be getting as much of those as I could into him.

* except to take into consideration any dietary requirements stipulated by his care team. FIL had a "fluids per day" target which we managed (by a mixture of threats and enticement) to adhere to.

Best wishes with it.

https://community.myfitnesspal.com/en/discussion/10326769/are-you-a-hard-gainer-please-read/p1

This could help.