I had the same cancer and treat 7 chemo and 35 radiation and a treach Also went for hyperbaric oxygen treatment 2hrs-a day 5 days a week for 60 days saved my voice box also had a feeding tube which stopped my weight loss and gave me strength to fight back Be there for him it’s a difficult and emotional thing to go through but it will get better be patient and all taste will come back takes time and rest last thing to come back is energy.Keep the faith it gets better