This declaration shows a real maturity on Charlie's part. During his relationship with Mary Elizabeth, Charlie hoped to make Sam jealous, but now he's just worried about her. That's assuming that he isn't just writing this to convince himself—but that's another discussion altogether.

Bill feels he can talk to Charlie as a peer. What do you think of this relationship? Does Bill assume too much maturity in Charlie, or does he just see his potential?

We doubt Bill would have objected to a hug, but Charlie doesn't try—simply because he's never hugged another non-family adult before.