It seems that aa.com was having an issue displaying reservations, which may now be resolved. (Earlier today aa.com was showing that I had no reservations, even though I have quite a few.) If that doesn't work, you can pull up the reservation if you know the confirmation (PNR), which is a series of six letters. And if you don't know that, you can simply go to the flight status page on aa.com and plug in STT as the origin and ORD as the destination (assuming he's flying to O'hare), and figure out what combination of flights he's on.