First I would like to thank everyone who has replied to this thread, whether it be some friendly advice or encouragement. Thanks!!
Some people have suggested giving Fred the Boot. I'd like to avoid that, if possible. What I'd really like to do is get together with the other players before game and discuss the issue. I hope to do that this week. My main worry is that nothing will get accomplished; two of the other members of my group are very close to Fred, having been friends with him for years. I myself have known him for a while, and think he's cool overall, even though we don't hang out outside of game.
Fred is very sensitive to criticism, and I know that any sort of talking to will make him feel like he's being attacked. Two of our group are his close friends, and that makes me think that they will be uncomfortable with the whole situation.
Ultimately, whether he is kicked out, chastised, or ignored falls on the DM and the others in our group. Were it up to me, I would probably drop him. If I were DMing, he would have been dropped already. I don't want to, because is he a good role player, but the constant tantrums are horrible.