I don't like how her wrist cocks back before entering sort of a weak trophy pose. While it might be something of a strength issue, I'd encourage her to keep her hand in a neutral position with respect to her forearm and that might help her trophy pose.
Let her see how the hand is allowing the racket to flop back and encourage her to keep her wrist in line with the forearm. In the trophy pose, the face of the racket shouldn't be open toward the sky. On edge or even slightly closed is better in my opinion.