Becki, can I point out that it doesn't sound like he said a single thing about stopping. Just that he was sorry. And that he's sorry for being a drunk; not that he's sorry for his actions, not about how its affected you all. He didn't say anything about changing - or even trying to change.
All he did was pour on a guilt trip to the entire group sitting around the table. If he really accepted any part of his role in this, that is not what would have happened. What he did was essentially say "You're leaving. It's you. It's all your fault." Had it been anything other than a major attempt to guilt you into staying, it should have been more along the lines of "I understand that you will be leaving because of my [behavior drinking] and [impact to your lives]. I will figure this out."