This was posted on alt.callahans by Andruschak, who says, “Yes, it is a very old joke.”

This is the way I learned the story way back in 1959. Anyhow, one day this Irishman comes into the bar and ordered three beers. He slowly drank them one after another. He ordered another three beers, same thing.

After a few evenings of this, somebody finally had the nerve to ask why he ordered three beers at a time, since the last one must have been quite flat when he got around to it.

“It’s for my two brothers who left for America. We agreed to always drink a beer for each other as long as we were alive.”

But, the night came when he ordered only two beers, and the entire bar fell silent. He ordered another two beers. Silence. He ordered another two beers, and the bartender finally expressed his sympathy for the dead brother.

“What? Dead brother? Gosh, I’m sorry I didn’t explain. No, no, my two brothers are alive and well, I assure you. It’s just that I’ve given up beer for Lent.”