Just so you are aware, after the course of radiation treatments is done, you can expect your husband to continue downhill for typically another two weeks. He may feel that something has gone terribly wrong but this is actually expected. Radiation continues to do its damage.
My eleven year old daughter noticed at the time that her Papa was miserable and hadn't laughed or smiled for many weeks. She was determined to change that. So she took her stash of cash she had saved from odd jobs and gifts and on her own went and purchased a DVD collection of Pink Panther movies for us to watch. It physically hurt a lot to smile and worse to laugh but it was worth it as a turning point in my recovery. Who could not laugh at such nonsense? You know Inspector Clouseau will never make it across the moat to the castle but he keeps trying ever inventive ways, always to failure.
The first time I could taste something good was about two weeks out, chicken soup. My wife saw tears on my cheeks and thought something was wrong But no, everything was going to be alright. Courage.