From About.com:

"Many times when family and friends try to "help" alcoholics, they are actually making it easier for them to continue in the progression of the disease.
This baffling phenomenon is called enabling, which takes many forms, all of which have the same effect -- allowing the alcoholic to avoid the consequences of his actions. This in turn allows the alcoholic to continue merrily along his (or her) drinking ways, secure in the knowledge that no matter how much he screws up, somebody will always be there to rescue him from his mistakes."