Ethics: How to deal with a professor who will not accept their inaccurarcy in judging my work?
Your professor is not being "unethical".  It's possible he's a difficult person but ethics is not a part of this.

There's a pretty good chance that if your professor says your proof is not correct, that it really isn't.  And he may not be as unhelpful as you think.  Students sometimes think an instructor is unhelpful if they don't give them the answer any time they're stuck.  But simply giving you the answer won't make you a better mathematician.  Forcing you to keep plugging at it until you find the answer on your own will make you a better mathematician.

My advice:  Consider the possibility that he's right, you're not and that he wants you to keep working at it until you solve it on your own and go from there.