Eli writes Juliet to thank her for blocks of wood she sent. He asks how Juliet found so many kinds and shapes of wood and says that the wood came at just the right time: Kit wants him to carve her a ferret. He asks Juliet if she has an animal she'd like a carving of and offers to carve her a mouse.
Eli's thank-you note shows that like the adults around him, he also takes part in caring for Kit by carving her toys when she asks. In this way, he acts like an older brother or cousin and becomes part of Kit's family.