We don't really know that. Since there's no evidence otherwise, one can assume I (if one really cares to go to such lengths) that Anthony is in his bedroom getting ready for Reno under the supervision of Aunt Connie, neither having any idea what is taking place on the lake. Since only Michael knows a shot is about to ring out...only Michael notices the sound of the shot. After recovering from the horrible act that was just committed on his own orders...he gets himself together and brings Anthony to Reno while Uncle Fredo goes fishing out on the lake. Don't think he couldn't pull it off.

Hours later, Neri returns alone, bringing with him the aweful news that Fredo fell out of the boat and drowned.

But...I don't think we need go to those lengths.

Does anyone else?

Apple