How do you know where the line is between 'helping' and 'enabling'?
Anything that makes it possible for the alcoholic to continue drinking is enabling. It's as simple as that. That includes most of the things in the answer below. The third answer is right on. I've worked with alcoholics and addicts for nearly 20 years, and I'm a recovering alcoholic myself, so this really comes from "personal experience."
I have three close relatives that are alcoholics so this comes from personal experience. There isn't a lot that you can do to help an alcoholic with his alcoholism or that path his life is taking as a result. Helping will be anything that assists him without making his pursuit of alcohol easier. Moral support, trying to make sure he eats and gets vitamins, encouraging him to drink water, getting him out to do things away from drinking (like taking a walk, playing a game/sport, seeing a movie or anything low stress involving human interaction), and generally letting him know that you care and want to help but that you see alcohol as a detriment to his life and will not support that habit are all helpful. As is an attitude expecting him to be responsible for his life and his actions. Enabling is anything that makes his alcoholism easier. Providing money or excuses, allowing him to feel that the world owes him better or that problems that he causes are not his fault, or that he is high-strung/ lives a high-stress life and needs alcohol are all enabling. Unfortunately most of the "help" an alcoholic will ask for or allow you to provide is actually enabling. Ask someone whose judgment you trust but is not as closely involved what he thinks. If you are very close to that alcoholic not crossing that line can feel heartless, cruel and spiteful. Especially if the alcoholic is telling you how "unhelpful" you are being. Al-Anon is a support group for those close to alcoholics and can be very helpful for you. Check the yellow pages.
The short form of the above hard-earned answer is, don't do anything for them that they should be doing for themselves. Don't cut them any slack because they're drunk or hung-over. Don't call in sick for them, or bail them out of jail, or tell lies for them about anything. If you do feel heartless, remember that an alcoholic will ruthlessly use anyone they know to justify and continue with their drinking. Let them stand alone. When they finally make such a mess they can't clean it up, they MAY choose a different path. However, many don't. That is not your choice.
This answer, by the discussion nature of it, may help you clearly see the different between helping, and enabling. If you are overly concerned about the well-being of another person or live your life to meet the needs of another person, while denying your own needs, you may earn praise from those around you. But if you are unhappy with your relationships and struggle to find more balance, you may be struggling with codependency. Enabling is the engine of codependency.
The word "codependency" evolved from the word "co-alcoholic," a term commonly used to describe a person in a close relationship with an alcoholic (or drug addict). Co-alcoholics naturally attempt to cope with the alcoholic's dysfunctional behavior by enabling - controlling, protecting, and compensating for the alcoholic's problems. Many people in adult relationships with alcoholics grew up in an alcoholic home, and as a result, exhibit learned codependent behaviors in their relationships.
Growing up in an alcoholic home is one way to be affected by codependency, but other health conditions and psychological problems may contribute to the development of codependency. The personalities of family members and the types of problems they experience shape the codependent behaviors.