About 20 years ago I reported for a ferry from a Large Airport in the North West, my base, to a Similar Sized Airport in the South East, the captains base. The Captain, who was quite famous for his boozing, had clearly not had too much sleep the night before. He Told me I could fly it down. I refused. I figured it would be better for me to monitor him and comunicate, rather than let him. But I really hoped he would go sick. He reluctantly agreed to fly. So I let him, remember it was only him and me on the aeroplane. He managed ok, but I think he leaned his lesson. He left shortly after.
But, and I ask you all to consider this. Very few aviation incedents indeed have had consumption of alcohol as a contributary cause, let alone a primary one. Indeed when I was working in my airline's flight safety office and reserched the subject, I could find only one such incedent involving a passenger carrying jet transport.