You might be surprised. My cousin (who is like a brother to me, we grew up together) is now on his way home from Iraq and is a marine. He is very similar to your brother in the sense that he's very traditional, republican (though he's starting to rethink his political views after Iraq...), and doesn't take change very well. I thought he'd hate me when I told him.
But he said "that's cool....does that mean I can teach you how to wrestle? Do you want to learn how to shoot and stuff? That'd be cool. I guess I'm supposed to call you Lane now?"
And that was it. No problems. Like I said, I was REALLY surprised....but you never know.