Appoint a designated driver.
apologize to them
A responsible person
That is a decision that you both need to talk about. Because this is a two person decision.
Each person should be.
The CEO is the top person in the company, ultimately responsible for it.
Responsible person on shore.
The person that went should....because he or she is taking a risk.....or the person should get a crazy check
Is the waiter or cook responsible when people over consume food? Should they be sued if you develop problems from obesity? To answer your question; presumably the person/people in question were of age and legally asked for and were served alcohol by an employee of an establishment that serves alcohol. If that is indeed the case, it seems doubtful to me that they can be held responsible for what the patrons choose to do, drunk or not.
First and foremost, the person must have a well-formed conscience, one that has been grounded well to the persons faith and laws. Second, that person must know when to implement his decision. It's called timing. That person should always be impartial in decision making. Last but not the least, that person should have a compassionate heart.
The short, and most applicable answer, is Everybody - every Employee. There should be an appointed person, ask any Manager who is the person responsible
Alcoholics should avoid oral application of alcohol.
They should politely say "No thank you."