and Lover of his "Baby Sister".

He likes to:

feed her (his crackers)

bathe her (and get a little wet himself)

rock her ("stop crying! stop crying!" while frantically rocking her chair)

show her toys (mom says "please don't lay your trains on your sister's face)

and tell us what she's doing in the car ("eyes open" minutes later "eyes closed" minutes later "eyes open" minutes later "eyes closed")

But the best part about LB, Lover of Baby Sister, is his willingness to pitch in.  Husband changed her on the couch and left her there to fetch new clothes and from the other room he heard LB...

"Hello, Baby Sister"

...

"Be gentle"

...

"Good Boy"

...

"I GOT HER!"