will be much better off if he already has good self-knowledge and has accepted that his current state is his current state

Everything here turns on the meaning of "accept". Does it mean "acknowledge as a possibly fixable truth" or does it mean "consciously endorse"? I think you're suggesting the latter but only defending the former, which is much more obviously true.

he wants desperately to maintain that, say, he doesn’t care about status and that only utilitarian expected-global-happiness-impacts affect his behavior -- a surprisingly common nerd failure mode

Is the disagreement here about what his brain does, or about what parts of his brain to label as himself? If the former, it's not obviously common, if the latter, it's not obviously a failure mode.