Sorry guys, but assuming a few conditions were met (and it sounds like they were) this was legit:
Robert's Rules of Poker, Section 3 - General Poker Rules (Dead Hands) (http://www.homepokertourney.com/roberts-rules-of-poker.htm#DEAD_HANDS) (emphasis added)
2. Cards thrown into the muck may be ruled dead. However, a hand that is clearly identifiable may be retrieved and ruled live at managementís discretion if doing so is in the best interest of the game. An extra effort should be made to rule a hand retrievable if it was folded as a result of incorrect information given to the player.
The other player announced call and the hand was mucked in error so I think it's reasonable and in the best interests of the game (though maybe not in the best interests of your friend) to retrieve the hand if at all possible.
Whether the hand was "clearly identifiable" or not is a bit of a point of contention - normally you'd expect the cards to be identified without turning them over, taking the entire muck to another table seems a little strange. Still, he announced he had AQ before
he realised his cards were gone and the rules don't specify exactly what "clearly identifiable" means or the exact method for retrieving the hand so unless anyone doubts he had AQ or unless the suits didn't match and played a role, I don't think there's much grounds for complaint here.
Note that the Estelle Denis hand may have gone a different way if the cards the tournament director checked had've matched her claim: he was clearly open to a ruling along those lines, otherwise he wouldn't have even looked in the first place. We'll never know if she actually had aces or whether she was attempting a gargantuan angle shoot.