My situation is similar to @gareee314 , but not as severe, so far. I'm only 3 months out from proton radiation on the left side of my face and neck after a tonsillectomy. I can no longer hock and spit phlegm and mucus. My throat opening is much smaller.
I keep a glass of herbal tea next to my bed to moisten my mouth and throat over night. I also use a saline spray before bed. I try to gargle normally as an exercise in the hopes that it will help restore my anatomy.
But it is an uncomfortable sensation. Especially after brushing my teeth in the morning which is when I would normally expel mucous by spitting it out. I hope it improves over time.

Wishing you and your husband the best.