Is Raymond a static or dynamic character in "Raymond's Run"?

Raymond is a static character.  
A static character is a character that doesn't go through any kind of inner change (or changes very little). Readers don't see any character growth or development in static characters.  
I believe that Raymond is a static character. He is mentally disabled in some way, but the story doesn't give specifics on that. His disability serves as a way to show why Squeaky is so protective of her older brother. It's clear that she loves him, and he loves her in return. By the end of the story, it is Squeaky's opinion of Raymond that has changed.  After witnessing him run, she now sees the potential in Raymond.  Raymond, on the other hand, doesn't have an epiphany about Squeaky. She is the same little sister that she always has been. He loves her dearly, and he supports her unashamedly.

Raymond is hollering from the swings cause he knows I’m about to do my thing . . . 

Readers also get to see that Raymond loves running "with" Squeaky.

And on the other side of the fence is Raymond with his arms down to his side and the palms tucked up behind him, running in his very own style, and it’s the first time I ever saw that and I almost stop to watch my brother Raymond on his first run.

I realize that Squeaky says that is Raymond's "first run," but I've always gotten the impression that Raymond's run that day may have just been the first that Squeaky finally noticed. Raymond runs because Squeaky runs, and it's his way of bonding with his sister. I don't believe that is new emotional ground for Raymond, which is why I believe that he is a static character.