Sure, he changed hers when all was said and done. Not by when Winter arrived, and David acted, which was my original point.
What's that even supposed to mean?
They were changing each other prior (Tess event, Ellie first shot and sniper event, Henry and Sam event, etc) and after to the end just as well.
David was just a punch bag for Ellie to grow a bit insane and lonely, until Joel's come back :D