Tobi is not freaking Obito, guys. gonk
Sasuke isn't going to die. Not with the kind of manga this is. Not with Naruto and Sakura dedicated to saving him. Not while saving him has practically become the point of the manga. He'll be back in Konoha in the end, although I'm not entirely sure if he'll be the one to kill Itachi, or what he'll have to go through to get there. But Sasuke isn't the evil baby-eater he seemed like at the reunion. Suigetsu practically exists to make fun of how evil he isn't. (Karin is there so Sakura fans have something to hate, lol)
So, for better or worse? Sasuke's not going anywhere.