My experience has been that a lot of those "Captains" are really
weak pilots. They seem to try to hide their insecurities by being a real hard-ass to their co-pilots. You can take their crap until it
becomes a safety issue and when it does, talk to other copilots who flew with him before. If they had similar bad experiences
with him you can build a case against him and turn his ass in. Changes are he/she might already be on the Union/Company
sh*tlist. Good luck.