@lizzyj58 pinpoint aka proton radiation wasn’t widely available when I was treated. It is now within reach of most of the population in the US and when it comes to head and neck cancers, highly recommended to limit damage.
After the radiation therapy you can expect him to continue to go downhill for several days to perhaps a few weeks before the recovery starts. Add Chemo to that schedule if that is the recommendation and you can see this going into the next year a bit.
Ensure his oncologist has specific experience with head and neck radiation. It is vitally important. If the answer is less than yes, go elsewhere.
Proton or photon for your husband?