I feel you @princessmewmew. I know I have a lot of patience and empathy for people and their shortcomings but for me at least Rules are Rules. And he knew the low down on what would happen.
Of course it does not hurt to see if he may need help with a drinking problem outside of work. But I think I would exercise the Rules of your Employment in this case ( if it were me)
You are very right. Rules are rules. And it is unfortunately my duty to report this. And as you say - he did know what would happen, yet he still took the risk!