The talk should occur when the person is sober. Specifiy behaviors - that cause you to be concerned. Speaking in generalities or preaching probably won't help. List positive points about the person throughout the discussion. Expect a lot of excuses - and minimization of the problem.
Most people are reluctant to admit that they have an alcohol problem.
Don't be put on the defensive because you drink yourself. Refer - the person to a professional. He's a happy drunk By believing these statements, significant others often avoid confronting the problem drinker and consequently support the inappropriate behavior. The following are the stages of the disease and the symptoms typical of each.