Hi,
I attended my first National last year and it was great.
I also recommend a 1-day pass, if he wants to come back you get buy a pass the next day.
I'm sure as a sports fan he will be able to appreciate the stuff on display. Auction companies show 100,000s of dollars of cool memorabilia, some of which might interest him.
Last National you had the opportunity to hold a Ruth game-used bat, which was really great, I'm not sure if that's coming back this year.
-Owen