Yeah, you see at the beginning when Sin attacks dream Zanarkand, Auron is speaking to Sin and says "You are sure?" then Tidus ends up in Spira, so that "you are sure?" bit suggests to me, Sin/Jecht is telling Auron it's time for Tidus to go to Spira. Auron was sent to watch over Tidus, as he promised Jecht he would. I think in one of the flash backs or Jecht spheres Jecht does actually say he wants Auron to bring Tidus to Spira, I may be wrong though.
Plus Auron had already met Yunalesca and found out the whole situation revolving around summoners and what-not, causing him to attack her and get pwned. So the odds are he probably does know about the dreams, but he's not the type of guy who reveals alot really, he lets Yuna & Tidus develope their own "stories" without telling them what will happen next, and what's waiting for them etc.
Plus Auron had already met Yunalesca and found out the whole situation revolving around summoners and what-not, causing him to attack her and get pwned. So the odds are he probably does know about the dreams, but he's not the type of guy who reveals alot really, he lets Yuna & Tidus develope their own "stories" without telling them what will happen next, and what's waiting for them etc.