It would appear to be a good dream he gives the turtle (The dream is of their love, not the turtles demise), and it's possible the little girl might do important work as a nurse.
As I said, that's what I like about this sequence, it highlights that Dream does not have human priorities because... well, because he's not human. He's the Lord of Dreams, but takes as much pride in his role as Lord of Nightmares, he created the Corinthian to scare humanity, and his only regret when he unmade the mass murdering monster was not for the lives lost, but that the Corinthian had failed in his design.