Yes as the other poster said, the answer is no. Your friend will have to go to T2 check in area first. He cannot access it from T1. You will get off at T1 AREX train stop for AA flight. He can go to the check in area and say goodbye to you, but then he still has to take a 20 minute bus from T1 to T2. If he stayson the train and says goodbye there, it's just 6 minutes for him to get to T2 to check in for your KE flight.