I'm about 6 months out of treatment for tonsil cancer ( left side, stage 4a), so I know pretty much what your husband is about to go through. I had chemo (cisplatin) and radiation (7 weeks IMRT). After about 4 weeks, I had to quit working, but I have a physically demanding job. With a desk job, I might have been able to work for longer, but at some point, he probably will not be able to work for awhile. I was out for about 5 months, I could have gone back sooner, but a had a nasty infection crop up in my throat that set me back about 3 or 4 weeks.
Make sure he keeps his weight up. If he's having radiation on his throat, he will have trouble swallowing, so you may have to talk to the docs about a feeding tube. Make sure he swallows something every day, as it is possible for the body to forget how to swallow. Make sure he stays hydrated. The nausea from chemo will dry him out. They can help with iv's but make sure he keeps water or gatorade with him always. The radiation will burn his neck, find some Aquaphor lotion for that. He will alsao get dry mouth, ask for a prescription for Salagen to stimulate saliva production and have him use Biotene mouthwash and toothpaste, they are made for people with dry mouth. He may also have a lot of pain in his throat ( I did), dont be afraid to ask the oncologist for pain meds, mine gave me a liquid form of oxycodone that was very easy to swallow and did the trick nicely. He will lose his sense of taste somewhat, I have heard that zinc supplements help with that. I have also heard that taking glutamine supplement ( a protein supplement) helps too.
Most of all, just be there for him. Support from family and friends helps a LOT. Try not to feel overwhelmed, I got through this just fine, your husband can, too. If you have any questions at all, we're all here for you.
Best wishes and good luck.
Mike