So he’s giving up his liver?
So if he spaces out a glass of beer every two hours or so, it will be plenty of time for the liver to metabolize the alcohol and get about a hour and a half of rest.
Or he could choose to have two beers every four hours. This would give the liver three hours of rest for each one hour of work.
I assume eight hours of sleep a day so during sleeptime, the liver will get an extra long rest.
So this could be safely done. Maybe a schedule could go something like this:
7AM (Breakfast) - Two beers
11AM (Lunch) - Two beers
3PM (Snack) - One beer
7PM (Dinner) - Two beers
11PM (Bedtime) - One beer
That would be eight 12-oz beers per day. Caloric level will average around 1,200 per day. Definitely enough calories to survive for 40 days but the man will be hungry!