If Fredo knew what was about to happen why would he stay in the boat?

3 reasons for staying in the boat-

1) he was ready to die for his crimes; in
which we see Fredo acting bold for the
first time on film; or:
2) he was not ready to die, but knew he had
little choice in the matter and decided
to die like a true sicilian; or:
3) he did not know and simply wanted to fish

Ok, which sounds more like the Fredo we all know?