Three brothers tradition

A man walks into a bar and orders three beers.
The bartender brings him the three beers, and the man proceeds to alternately sip one, then the other, then the third, until they're gone.
He then orders three more and the bartender says, "Sir, I'm just wondering why you order three beers at a time? I can bring you one at a time if you wish."
The man says, "You don't understand. I have two brothers, one in Australia and one in the Ireland. We made a vow to each other that every Saturday night, we'd still drink together. So right now, my brothers have three beers too and we're drinking together."
The bartender thinks it's a wonderful tradition, and every week he sets up the guy's three beers. Then one week, the man comes in and orders only two. He drinks them and then orders two more. The bartender says sadly, "I'd just like to just say that I'm sorry for your loss."
The man replies, "Why do you say that?"
The bartender says, "Well I've noticed you only ordered two drinks instead of your usual three."
The man then replies "Oh jeez no! My brothers are fine -- I'm just off the drink!"