The chitlins have been spending a lot more time 'together'.  And what I really mean is that Sean has finally noticed that Carter is more than just an eating and crying machine.  He has recently discovered that she is in fact a little person, and has been interacting with her a lot more.  He sits and talks to her, brings her stuff, and sometimes makes rudimentary attempts to play with her.  I think he is going to love it when she gets a bit bigger and walks around.  He doesn't get much exposure to other toddlers, and having a 'live-in' playmate should be a lot of fun for him.  As long as she's not a tattle-tale, of course.