Hello sandyjr. My heart goes out to you all. I will share my story quickly and hope some of it might help. I had my second squamous cell carcinoma on my tongue identified 10/2021. After discussing my treatment plan locally, I reached out to Mayo. Best decision. I had a partial removal of my tongue (leaving out the medical terms) and then a rebuild with muscle and vein from my arm (same surgery). I woke with a trach and obvious swelling and pain in my mouth and arm. I was released from the hospital on day 6 and the trach removed. The 6 days with the trach were difficult, but I would have to say worse in the beginning and easier to deal with on following days. The phlegm stuck in my throat, required to cough to clear, was difficult. Mayo's oncologist reached out to me advising that my cancer was aggressive, and a plan was set up for 30 radiation treatments (M-F) and chemo once a week for 6 weeks. A feeding tube was "threatened" every week as I lost weight from not being able to eat due to mouth pain. I drank a concoction of high calorie additives and drinks, blended with ice cream. I cried as I drank it because my mouth hurt so bad. Fast forward to end of August 2022 when I hit 6 months from my last treatments. I would say that it has been hard and difficult and basically sucks but family support is what has brought me through. Also, my mom and I stayed at The Hope Lodge in Rochester, MN which is owned by the American Cancer Society. Staying there was a blessing. Being able to talk with others going through similar journeys. It is free to stay there, and the Mayo has to refer you to them. I hope something here helps.

Feeding tube is an excellent idea and he will learn quickly to deal with it. The alternative is to slowly starve as eating will not be a good experience after a couple weeks.
"Difficult and unpleasant", his handlers are being honest with him. Many of us on this site have been through "difficult and unpleasant" so if he feels the need for help or encouragement, please get him connected with us or others. It is not an easy path but it is the right path.
Courage! This may be one of the toughest battles he will face in his life but he will come through most likely. The alternative is to search for a nice place to be laid to rest. But whilst in this battle and the weeks and months to follow, I think as most can agree that this battle will make him stronger, appreciative of life more, and be grateful to those around him.
He may never get back to "normal" but he will have a new normal and life can be fine with a new normal. Let's get through the hard part first, the treatment. After radiation he most likely will continue to go downhill for a couple of weeks and then slowly, bit by bit, recovery begins. He will complain. He will fuss. And if he is human he will cry. But giving up is not an option.
Good luck to him. We are here. I'm twenty-one years out from my cancer and two years since my last cancer related repair. If I needed to go through that hell again I would. I'd cry. I'd fuss, but I would fight. God be with you both.