Studies have indicated that
HPV+ SCC responds better to existing Tx and (therefore) has less chance of recurrence. Some doctors use this to put off a ND until post Tx IF the Tx didn't work. I doubt that would have made a difference in your H's recommendation due to his nodal involvement and it's spread.
There are talks of studies with
HPV+ patients to lower the radiation dose to ultimately arrive at the lowest dose that kills the cancer therefore reducing the side effects. None have started as of yet though so most, if not all, doctors still go with the 70 to 72 Gys spread over 7 weeks and in nodal involvement, chemo is almost always added.
If he's already been tested let us know when the results come back.