How to deal with this situation?

My view on something like this is that if he is ashamed to be friends with you around his other friends,he's not that good of a friend himself.Tell him that.I have never been one to care about others' religions(whatever floats your boat,you know?) so I might have a limited view on this situation.But if someone is trying to be what his friends want him to be instead of what he wants,he's not being a good friend to you.