However, unfortunately, in the end the cancer was growing even more aggressively than anticipated. Perhaps a cancer doctor can tell us what portion of the bell curve Job's cancer would be found in, that it was more aggressive than expected. If Job's approach would have 'won' most times according to his own utility function (given a random cancer, by selecting non-invasive approaches over surgery) then he could be more rational than appears in this particular Everett branch.

If this is that case than Jobs behaved rationally, bet right but still lost. This has almost nothing at all to do with Everett branches.