Dear
Donna,
Caleb was a spy in the Bible, in the early days of the Hebrews who came from wandering in the desert into the promised land.
I haven't read this book, and it is probably a little below his reading level, but something similar to this may be of interest as a depiction of the biblical story:
https://www.cph.org/p-18498-Caleb-Gods-Special-Spy-One-in-Christ-Bible-Story-Book.aspx
As for the actual "story" of
Caleb in the Bible, his name appears throughout several books, especially Numbers and Judges, which may be a difficult read for your
Caleb's age level.
I love the heart that you have for your grandson!
One other thought I had, does he have a nickname he prefers to be called? Or do you have a special "pet" name for him that he likes?