I had a friend from elementary school to high school who was rather odd. He walked as though he had "had a pole up his butt" (in the words of his mother), carried a hard shell igloo cooler as his lunchbox (packed with candy bars and two bottles of soda every day), had a rolling backpack long before it was even close to commonplace, didn't talk to anyone but me and very occasionally my other friends (but usually only in a response), had the kind of acne that scars the face (and didn't treat it), and, after reaching puberty, understanding a word he said was neigh impossible. His mom had a bowl cut and always wore large dark sunglasses and a gray T-shirt; although his dad just seemed like an old country guy with a mustache.
My other friends and I always joked that he was in the witness protection program because no one had ever been to his house, his parents were reluctant to let him go to others' houses, and, even when the school required his address for things like Science Fair, his parents made him use a P.O. Box. His mother's appearance also gave the impression of someone incognito.
One day around March in high school, he was out sick for a few days. But he never came back; he was out for the rest of the year. He wasn't at school the next year or the next either. No one at school, save our small friend group, ever mentioned him again. Since his family was so secretive, we had no way of getting in touch with him: I don't remember if anyone had an up-to-date phone number for him, and he didn't have a cellphone since they weren't ubiquitous yet.
We continued to joke that he was in the witness protection program; however, now I am wondering if that may have been true. Over fifteen years later, I still have never heard from him or seen him nor have my friends, with the exception of one who claims to have seen him buying Doom 3 at Circuit City circa 2006. He has no presence on the Internet that I can find either.
What do you think could have happened?