There's really not much you can do to boost the immune system (in spite of what GNC might claim), the combination of chemo and radiation will clobber it for a while. Just make sure not to take unneccesary risks, like exposure to colds and/or flu, public places, (especially sick children), keeping your kitchen and bathrooms thoroughly disinfected, wash your hands frequently. If you have volunteer drivers, make sure that sick people haven't recently been in the vehicle he is traveling in. My wife also opened doors for me so I didn't have to touch any door handles.

He shouldn't have had to suffer. Adequate pain management is a basic patient right - demand it. The MO will typically manage all of the meds. Also clear with him first, any OTC meds you might be adding.

I don't blame him for being scared, only an alien wouldn't be. Many say that surgery was a walk in the park compared to radiation. The general rule is 1 month of recovery for each week of radiation. I didn't believe that at first but I'm a beliver now. I was on anti-anxiety meds the entire time I was in treatment - they really helped. The treatment can really kick your ass so anticipate that- roll with it as best you can. Keep focused that "this too shall pass".

Most chemo drugs to date are used as an adjunct and performance enhancer for the radiation (like Cisplatin or Carboplatin). Chemo by itself has not yet proven to be efficacious as a single treamtent modality for H&N cancer. They have come a long way with anti-nausea (emetic) meds.

Dropping 20 lbs., before he has even started radiation, is not good unless he was really overweight to begin with (and even then the flags should be going up). He should be having weekly meetings with a nutritionist as part of his medical team. Consider Carnation Instant Breakfast as well. Many have had superior results with products like Jevity. If you can get a presciption for it (like Jevity) the cost may be reduced or eliminated depending on your health plan. OTC things like Ensure or Booth they won't cover. Even with a PEG tube he should try to continue to take food and drink orally. The pain can be managed with "breakthrough pain" meds taken prior and/or topical "swish and spit" compounds like "Pink Magic". It is crucial to stay hydrated during chemo especially - 2-3 liters every day is what is recommended.

Keep a daily log of meds taken, food and drink consumption, anything unsual, and take his temperature at least twice daily. If his temperature goes above 100.5 degrees, he needs to see a doctor immediately. If he needs rehydration, a faster and easier route is to have it done in infusion (assuming that they are open when you need it), rather than the ER. They can infuse much more rapidly in infusion and it's a 1/2 hour vs 4 hours in the ER, not to mention the long waits and potential dangerous exposures in the ER waiting room.
Be sure that you take good notes and follow all of the doctors orders and presciption warnings and precaution carefully.

Stay in close contact with the MO about any problems that develop. I anticipated many of the problems ahead of time and had my own "pharmacy" stocked and ready to go (this way I didn't need to suffer over the weekend or spend time in the ER). A variety of pain meds, Diflucan (for thrush), Anti-acids - industrial strength (because chemo does a number on the stomach lining), Constipation remedies (because of the pain meds), decongestants, etc. There were more -this is just a basic list.

We all respond differently to treamtent so don't focus on just the horror stories you read here or elsewhere. Some here drove themselves to treatment every day and continued working (although that was a very small percentage).

Many of us survived chemo and radiation and are just fine and are leading normal, productive lives today.

He just needs to take it one day at a time and keep focused on the "now" and not the immediate future.