If I endow a professorship, they invest the money, but the principle and interest cannot be used to put a new roof on a dorm.
That doesn't answer the question.
$4.2 billion at 2% interest is $84 million every year.
Where does the money go?
I don't care how many times you mention "cow farts" with the appeal to absurdity fallacy.
You can pay 840 professors and scientists $100,000 apiece with that kind of money.
Has Brown University ever been audited?