He is not jealous at all. In fact, he is so proud of his lil sis that a coo sounds like a whole song to him.
He has much better common sense and hygiene practice than kakak. He asked if the pacifier is clean every time he sees us shoving it into baby's mouth. He washes it when he sees a speck of foreign entity on it. He only touches the handle and not any part of the pacifier which comes in contact with baby's mouth.
While I have an affair with the medela pump, he keeps her entertained. It really does make breast pumping more fun watching them "talking" and smiling and laughing at each other.
Every time he manages to get a happy response from her (usually a loud and excited shriek), he is as proud as a peacock.
He is disappointed when she is asleep. He can't wait for her to wake so he can have endless soliloquies with her (with me as the observing party).
He loves her so much that he thinks she is the cutest baby in his universe.
He loves feeding her (using the bottle lah). So much so he is wiling to drop anything he is doing (example: tv time) to fulfill this duty.
Are you impressed? Heck, I know I am!
And proud, too. :)