Arthur Havisham
He's starting to see that he bit off more than he can chew. He can't control Compeyson, and in fact, Compeyson is controlling him. Do you think it has crossed Arthur's mind that Compeyson is really only in this for himself and intends to cut Havisham out completely, once he controls Amelia's holdings?
Do you think Compeyson is only keeping Arthur around because he might still be useful? Once he's no longer needed...
Do you think a moment will arrive when Arthur regrets, for Amelia's sake and even her safety, bringing Compeyson into their lives? I don't mean Arthur regrets trusting Compeyson, only because Compeyson squeezes Arthur out; I mean Arthur regrets bringing Compeyson into his sister's life because Compeyson's a really bad person who is capable of bringing serious harm upon his sister.