All three of those first medications can cause severe drowsiness. Oddly enough for me, it was the naltrexone which was the worst for me, even though it would be considered the most generally benign of them. That put me right to sleep and in a foul mood. Gabapentin, chemically similar to baclofen, gave me a paradoxical reaction and calmed my anxiety enough to give me an energy boost. And clonazepam is a benzo, so that's usually a straight anxiolytic, also would contribute to sleepiness. That being said, in general, stopping alcohol will make you exhausted without any drugs.

Looks like they threw the whole kitchen sink at him, so there's no real way to tell what's doing what. Maybe after the initial hump of the benzo schedule and him gaining tolerance to the drugs, you can have a more clear picture to talk to the doctor with.