Tuition money is fungible. If a school gets 20% of it's funding from loans (no idea what the real number might look like) and uses 30% of tuition money to fund their endowment, then the accounting will show that all of the loan money went to fund operations and only cash payments went to the endowment.

We've already seen this in every state where lottery funds "go to education." The new money doesn't increase the budget for education, it only frees up some money to be spent on something else.