Fantasy illustrated children's book.

I made another post asking about but no one was able to help, so I'm trying to add more details. Looking for a painted picture book (possibly from the late ’90s/early 2000s). I remember it having a young sister trying to put her baby brother to sleep. Various animals take their turn, but the final helper is an alligator or crocodile that stands upright in a gondola-style boat, uses a pole to push it under a full moon, rocks the baby to sleep, and returns him to the sister. The baby is human, cover likely peaceful/dreamlike.