One of my friends is trying way to hard to be cool, and treats me differently now. What can i do?

Basically i am friends with this person who, until i became friends with them, was a follower their whole life. I was nice enough to give them a chance, so at least they aren't as quiet as before. But because this person was a follower and still is today, they'll do anything to fit in with a certain group of people. Because this group they want to be a part of is close knit, i guess my friend feels left out, as they might talk to him differently than they talk to eachother. But now my friend wants to be cool, and treats me the same way they treat him, by acting like i'm on a lower level than him, or are not apart of "his" group. He achieves this by making sure that he is at any social event i am at, and that he is at ones that i am not, purely so he can say that he was there. I've even started experimenting. For example, If i make a comment on his facebook, he won't comment back or like it, but go out of his way to comment on other people's statuses to show that he doesn't care. I don't know what to do. He pisses me off so much sometimes, but then acts like the nicest person in front of everyone. He overthinks every action he does strategically to look cool. I'm starting to think he is either a psycopath or has really low self confidence. Should i just stop talking to him?