Fredo didn't know.

And if anything, after Fredo's outburst in that boat house scene, Mike should have realized even more that Fredo didn't realize that there was going to be a hit. After that outburst Mike should have realized that his brother was dumb witted, weak and easily manipulated, and should have never made the decision to kill his own brother, his father's son, his mother's son. The thought of killing his own brother, especially one that was so dumb and simple, should NEVER have even crossed his mind.


C'mon now, even Neri, Mike's own cold blooded gun for hire, has a look on his face, when Michael gives him the nod, like, "are you fucking kidding me, I can't believe you're going to kill your poor ole brother."

What a cold hearted bastard!