Hitt,
Basically, it’s a matter of professionalism. It’s not your brief to deal with this if he isn’t under your authority. Being chummy about it is the last thing you want to do. I’d take it to the boss not even talking about the guy, but talking about the (twice) screwed up order and why that order is screwed up. That way the boss can’t come back to you when the ish hits the fan, because you have already notified him of the possibility. Maybe if you were best friends or something, you might want to have a quiet word, but that doesn’t seem to be the case. Your conscience should be clear as long as you do right by the company. jmo
Oh, and if the boss comes back at you, for bringing it to him: don’t stand for it.
I’d say, “Hey, he’s YOUR guy, not MY guy.”
This is his problem.