Not him, but I'm also a tracker school "graduate".
I learned a lot. It changed the way I look at the woods--now I'm always looking for tracks, and I'm seeing trails that I would have missed before. Tracking is really the only way to know everything that's going on in your patch of woods. It reveals a whole unseen world.
Tom Brown is legitimately skilled and knowledgeable, but he also exaggerates his abilities a lot. Grandfather wasn't a real person. Take everything he says with a grain of salt. Also, the school is pretty close to a cult. He talks about spiritual shit and the collapse of civilization a lot. I'm looking forward to the day it becomes a full-blown apocalypse cult.