Okay, that's an interesting one I haven't really thought about.
Like, I've thought about him vaguely in the sense of how he plays into other people's stories, but not his personal story.
The world is structured differently. The Pokémon World has unique sports and activities, not just the standard sports, and I think the Pokémon-oriented sports would be more important to people than, say, football. Smallville High probably has a PokéRinger team, and Smallville itself holds Pokémon Orienteering competitions fairly frequently, since they're surrounded by so much wilderness. Plus there's Battle Teams.
Whitney would probably be on the Battle Team, and if he took off from Smallville, it would likely be to pursue a career as a battler on the professional circuit, or to compete in the League, not to join the military, so he wouldn't be in the middle of any kind of deadly conflict.
Which creates some interesting opportunities for stories.