Hey Boomer,
I can totally understand your frustration. This is the place to be though, there are many experts here that seem to know more than most doctors. I'm sorry to hear about your frustration, and it's a sad place to be. As far as the drinking goes, I would think that the doctor's can give him something to take the edge off. From my experiences, I've learned that nothing can get you sicker and down faster than alcohol As far not eating, that is tough because I constantly had people rant about how I should eat more, but was so sick inside I could not take a bite! See if he will eat a veggie and fruit naturally blended drink- and if he can get some substance in, the lactulose should help.
As for the pain medicine, I would think fentanyl may be easier to process than pain meds. Methadone can have very high anasthetic benefits. Also, I was taking a medication called burprenorphine in the form of SubutexTM, that is similar to methadone, but i'm not sure. It is alternative to SuboxoneTM given to hep C patients for heroin maintenance. Just another possibility to ask your doctor about however, i'm not sure if it would would help in your situation and may not be beneficial. It did not diminish my appetite- and I was on it for two years for before quitting altogether. Good luck buddy, just keep doing the best that you can do.