You lost me there. Which school are you thinking of, because I can tell you that there is no boarding school - NONE - that even comes close to this description. In the context of >+3sd kids (starting at approximately 1 in 1,000), the typical boarding student at even the most selective school will be quite unimpressive, at least on intellectual measures. There are genius kids of course at boarding schools, but not very many at all. It would be bad for business, among other reasons. And no boarding school is going to admit an 8 year old (which I think is when he started high school), anyway.
Getting back to this kid, I found another article that confirms what I suspected - the family does not have the resources to do anything other than the path they’ve chosen:
Like I said, it’s not always easy to deal with gifted kids even substantially below this kid’s apparent abilities, but it looks like this family is trying to honor the gift they’ve received.