Form your own opinions. Don't base it positively or negatively off of someone else's opinion, stand up straight, be the bigger man and walk away.
I've always found it ironic for someone to tell the other person in an argument to be the bigger man and relent. Not saying it applies, but it does.
I guess he just needs you to point and push him in the right direction. You know, on opinions and stuff. EDIT: I accidentally a word.