Good question. Off the cuff, I can't think of a job that would befit a man such as Fredo. The quality that Michael was missing, that was pointed out to him by Hagen (in the novel) was how to say No. The Don counseled Michael that you can't say No to the people you love. But if you do, it has sound like a Yes, or you make them say no, regardless of the effort that it took. Taking that lesson and applying it to Fredo's situation might have solved the problem. The problem that I have with my own argument is that Tom's future was contemplated at great length between Vito and Michael. His being removed as consigliere was a move made by both for key strategic reason. Why didn't Vito, as father, take the time to consider Fredo's future in the same manner- regardless of his inability for important roles. Maybe Michael was simply conintuing his fathers ambivalence for Fredo.