I assume he/she is flying Cdn, not AA.

Cdn stickers -- particularly the vaunted "black" ones -- are issued to and valid "for use by Cdn ExecPlatinum and Gold members" and only to be accepted for upgrading non-members when they are accompanying a member who also using a sticker on the same flight. So the answer is: your friend is out of luck.

Given that AA is no longer an owner of Cdn, I doubt there would be much sympathy for making an exception of being "part of the corporate family". Since AA doesn't have international upgrades except on a "paid for by miles" basis for its mid and low level elites (i.e. Gold and Platinum) it is even more unlikely Cdn would honour your request on a reciprocal basis.

Parhaps a good hearted gate agent might be convinced if there were seats left prior to departure, but convincing a res agent to confirm an upgrade 72-hours ahead might prove a problem. Will the computer even confirm an R upgrade for a non-elite unless accompanied by an ExecPlatinum or Gold member?

When I was AC Elite, I gave a friend who was Prestige a couple of extra North American upgrades I had, thinking AC would let her use them since she too was flying on a full-fare Y-class ticket. They refused her because she wasn't Elite. However, I have also used the Elite syestem-wide certificates to upgrade two colleagues when we were all travelling on Y2 tickets from Delhi all the way back to Canada: myself and one to Edmonton, the other to Vancouver.

The bottom line is you have to have the elite status to use the special elite upgrades issued as a perk for being elite.

Then again, I suppose anything is worth a try at the gate...