My proposal for alternate punishment to two years in stir would depend on several factors.
What is his seniority, age and general history with the company? Senior, approaching retirement with good history? A 30 day unpaid suspension with requirement to take some alcohol counseling. Newby with spotty record and possible problems with past employers? Sayonara Sweetheart...don't look to us for a reference.
I think if his drinking had resulted in a crash with serious or fatal injuries, few would question the appropriateness of a jail sentence.