[Spoilers] [Theory] Itachi and Sasuke have already had their "talk".

[Orochimagus]

Yeah I had already pointed this out. Itachi did not need to use Tsukuyomi and could have released Sasuke with a mere Genjutsu. Though I think that Itachi is about to die, and we will see what happened between Sasuke and Itachi as a flashback.