If he doesn't want, it is one story. Another story may be because he may not be promotable to such position because of mentioned "prickly" behavior, which may

If he doesn't want, it is one story. Another story may be because he may not be promotable to such position because of mentioned "prickly" behavior, which may or may be not just engineering honesty and straightforward approach in contrast to bs(sugarcoating, ass kissing, exaggregating, sweeping dirt under carpet, etc) culture established in many companies.