That tells me nothing short of the Donship would have satisfied Fredo.
Do you really think Fredo believed for a second he could work as a Don? I think that his self-esteem was very low. And I believe that his main frustration was that he never got the kind of love from his father that Michael or even Sonny git. In fact as Puzo put it, Fredo was on his father's shitlist. And Fredo knew why.
