Echoing what Donna said, xrays and scans are only a small piece of the puzzle and by no means definitive. In my case the radiologist(s) had all kinds of concerns about different suspicious areas (and this after Tx). Stuff like: "...mild prominence", "...increased enhancement of uncertain significance", "increase in fullness in right base of tongue", etc. It turns out that it didn't mean anything except for the head & neck surgeon to take a closer look. Comparing scans is tricky because you may or may not have scar tissue on this one that didn't show up on the last one or you may even be in a slightly different position from the last or you may have some fluid buildup or you may have a different radiologist who interprets things differently from the last one, etc. etc. If he has ever had pnuemonia anomalies may show up on the chest x-ray.
Thank God they're being diligent but it can be unsettling. My head & neck surgeon informed me that his visual and palpation exam is the gold standard.
I lost over 60 lbs. His weight loss isn't bad. Under 20 lbs is considered acceptable.

It sounds like the chemo he is getting is the type that oxygenates the tissues making the radiation far more effective. It is an adjunct to the radiation. Conventional chemo treatments (the kind that goes out and poisans the cancer) are typically not that effective in head and neck cancers. I am a little confused by the frequency though, if it was Cisplatin (or Platinol), the usual course is 2 or 3 sessions administered every 3 weeks, starting simultaneously with the 1st day of radiation.

Mark is right - ditch the medical records or use them to ask questions from the doctors to calm your anxiety. Doctors usually always take the worst case, most conservative, approach (to avoid liability no doubt).

His mental state sounds pretty good right now and that is a positive thing. Try not to freak out and feed the negative aspect of it. He may very well suffer depression later on in treatment or post treatment. It is very common in cancer patients and there are medications to manage it. Your doctor or team should be recommending them automatically (along with anti-anxiety meds if required). At least they should be asking the "right questions".

A 6 pack a day is a lot of alcohol. Some people would consider that "alcoholic or problem" drinking. When he starts feeling better he may drift back to his old patterns or he may "self medicate". Not a good thing if one wants to avoid recurrence. I would get some help and counseling for this.

Typically people tend to underexagerate their alcohol problem. When they say they drink a 6 pack a day (at home), they forget about the 3 beers they had with lunch and the 2-3 beers they had at the bar with the guys after work.

Cancer survival has a way of forcing one to become honest about their habits (or dead).