hmmm...honestly(not trying to sound conceded or ne thing) i've never actually had this problem with him.So what is happening are you using their overdrives and then he gets a couple of turns in a row to hit you right? if that's the case i would bring out the aeons and have them use thier regular and special attacks so he only gets one turn at you. You can heal them this way and cause some damage and then when it looks like he will take them out in the next turn unload their overdrive. The only problem with this strategy is that you have to time your attacks correctly cause if he kills your aeon you lose a precious overdrive and it could cost you the battle. Normally in this battle my aeons use their overdrive and then he hits them a few times and they get overdrive again and i get like 2 overdrives with each aeon. He's not killing your aeons in one strike is he???