I liked the supporting characters you created and how they connected with Superman. It added an element that did more than just showing the two personas—Clark & Superman. The interactions, including what happened when he was transported via wheelchair to a sunny room in the hospital, actually served to humanize the alien more so than just knowing that he is Clark Kent. They also showed a definitive contrast between Superman’s goodness and the people who loved him, and Luthor’s evil and others who hated him.
While your story is complete as is, I believe it could be plumbed to a deeper level from several angles to become a richer, much longer tale!
Thanks for sharing!