he probably lacks the intelligence to be in management anyway.
LOL +1 Funny. Unless you mean he lacks the kind of intelligence, i.e. Emotional Intelligence, required in management. Even that I would disagree with, there are many different strengths a manager can have and no one is strong in all areas. A high EI manager may be good at reading how their staff feels about what they're doing but shit at strategic planning.
I don't see anything wrong with remaining a mid-level programmer, better to serve as a good example through your code and behavior than to suffer from the Peter Principle and "rise to the level of their incompetence."