> A close friend of mine had perfect scores in basically everything and Harvard turned him down on the basis of "we already accepted your older brother and it wouldn't be fair of us to take two of you".

I will go out on a limb and say that this is a narrative he shares to avoid embarrassment, and it’s probably not true from the Harvard perspective.

SAT scores and grades are only one part of the admissions evaluation criteria. How did he do in the others? What about his brother?

Something like this might happen if his high school had a certain range of slots for each elite school, and the school counselor decided to against advocating for him to get into Harvard specifically for some reason. That said, it still may have been a polite way of saying that he was not as good as his brother. Furthermore, if he was actually a compelling applicant, I imagine he got into some other elite school.

I really wish more people would learn about and appreciate the different evaluation criteria that elite schools use. These criteria aren’t perfect, but they strike me as being fairly dynamic.