Stubbs never had a horse as beautiful as you to paint. (5.4)
Captain Nicholls's admiration for Joey extends into the realm of art. He hopes to paint a picture that captures Joey's essence so that others might admire him, too. Hey, isn't that kind of what Morpurgo is doing with War Horse?
"[Nicholls] died leading that charge and you finished it for him. He'd have been proud of you." (6.14)
After the death of his friend, Captain Stewart praises Joey because he thinks that's what Nicholls would have done had he survived.
"They are the two best horses in the squadron." (7.2)
Once again, Joey and Topthorn are heaped with praise. Why do you think Morpurgo never shows a human soldier receiving any sort of honors?