Yeah, his whole replacement Catelyn thing is super creepy but he does seem to care. They've totally built up the pawn to player thing with her, and considering Littlefinger is like, the ultimate player I think she'll be the one to get rid of him. Fingers crossed she sits the throne in the end (because it's sure as hell not going to be Dany)!
People are saying that Joffrey dies in the second episode because George Martin is writing it, so I guess we'll see how things play out pretty quickly.