Texting him does have a result! The conditions are to talk to him in the map room (which triggers disapproval -- I know, I know, not exactly intuitive) and to have gotten positive approval from him at least once.
And I'm glad to hear you like him. He may not have flirt options (for now), but there's still plenty of opportunities to spend time with him, and who knows what feelings will blossom, old or new? ;P