I actually decided to just fill out the TSA Pre Check form online, and make an appt with the local TSA Pre Check company in my town. The appt was yesterday morning. It took maybe 5min with my son. The guy there took his pic, fingerprints, etc, and we were done. He did have him "Sign" the best he could. They said I should have the number in 3-5 business days. If this works, I can't believe it was so easy. I just answered "Yes" to the competency question online and that was it(considering we are his Guardians, with him 24/7, and are competent. Once at the appt, no questions or problems, other than getting him to fingerprint.

I'll let this thread know when we finally have it.
If this works, any adult with a cognitive disability, who travels more than a couple times/yr, should get this. This has been troubling my wife and I for years, and all we had to do is try. I hope this paves the way for other parents in my situation as well.