Actually, alcohol in and of and by itself is not a carcinogen. It is a catalyst for other carcinogens multiplying their carcinogenisis properties. As long as the beer consumption is moderate I would worry more about the dehydration it causes than anything else. I agree with Sheldon in that missing a doctor's appointment at this point is not good and much more cause for concern. As far as the PEG tube goes, it's probably precautionary. It's better to get it in now so that if your Dad has problems with swallowing and keeping the weight on during treatment, it's already there to be utilized. While I didn't have a PEG myself, I understand with some folks it litterally turns out to be a life saver.

-Brett