The definition alcoholic is complicated. For most people, being an alcoholic means that there is some form of either alcohol dependency (need for it to feel normal or to prevent withdrawal), or the alcohol must adversely effect their lives in some way. For example, if your dad's drinking ever caused him to miss work, be late to a meeting, or over sleep, then he may be classified as an alcoholic. If alcohol has ever put a strain on any of his relationships, then he probably is classified as an alcoholic. If he has ever felt jittery or abnormal in any way if he doesn't drink, then he could also be called an alcoholic.
Although I can't tell from your question if your dad is an alcoholic, I can say that he drinks excessively. Physicians have defined two drinks (wine, beer or hard liquor) as the most someone should consume in one day. Thus, your dad exceeds that by a lot. If he were my patient, I would actively try to reduce the amount he drinks.
I suggest that your dad schedule an appointment with his primary care physician
. His doctor
has a screening tool that he or she can use to determine how severe his alcohol problem is and come up with an appropriate treatment plan.