Hello Kate; The caring involvement of family is one of the best medecines we have in our fight with SCC. You will have plenty of time to help your Dad out as his recovery is likely not going to be a quick thing. Some wise person on this board told me to "take a month for every week of radiation" and I have found that rule of thumb to be pretty close.
After his rads finish your Dad will continue to experience side effects, likely the worst so far of his TX, so don't let him throw away the pain meds. But it does slowly improve, the crazy taste buds that have gone on strike return...or at least most of them do. The fatigue is REAL and rest is important. He may enjoy having the lawn cut or the yard tidied.
A pot of simple plain soup (no spice) brought a tear to my eye when my friend dropped it off.
When I think about it, it's so true, actions do speak louder than words. Your own practical response to his situation will speak volumes and your wonderful loving support is a treasure.

Keep in touch, hopefully we survivors can be of some help to you.
All the best,
Fran