Don't worry, there's lots of great shows for boys in fisrt grade:
Pokemon, Digimon, The Flintstones, The Jetsons, Scooby Doo, Looney Toons, Yogi Bear, Spongebob, He-Man, Rugrats, Rocko's Modern Life, AAAAAHHHH Real Monsters, Doug, Wild Thornberries, The Simpsons, The Critic, King of the Hill, Futurama, Ruby Gloom, Lloyd in Space, Arthur, The Smurfs, The Mario cartoons, The Legend of Zelda series, Earthworm Jim, Animaniacs, Invader Zim, Pinky and the Brain, Ren and Stimpy, Reeboot, Fraggle Rock.
I would have suggested Murder, She Wrote, as my son liked it at that age, but chances are 99.9% your son wouldn't like it. (Mine was just weird about that, lol).