It’s not (just) about the money, which is where “longtime parent” becomes even more important.
You certainly can’t operate a school without money, and admin knows that; but (both out of practicality and because of the somewhat traditionalist bent these schools tend to have or aspire to) they know that you also can’t operate a school without a student body, some really committed parents, ideally a solid reputation in the area you hope to draw future students from, etc.
That’s the real problem for Jarvanka in this case: it sounds like a substantial portion of the parents were against what they were doing; which meant that coddling them would have required admin to tell a major slice of their committed parents that, yeah, they were cool with them and their children potentially dying in order to please one family.
That’s a tough sell. A school community tends not to be immune to mercenary interests, squeezing a few inadequate scions through the admissions process, maybe agreeing that boys from good families sure will be boys sometimes; that’s definitely on the table; but outright telling a major chunk of the parents who are most worth hanging on to that they don’t matter and can shove off? I doubt that is on the table; the school has its future to think about.
Even in the really sordid cases of one student being thrown under the bus in favor of another(eg. most stories involving student athletes, sexual violence, and an astonishingly compromised disciplinary process); it’s generally the case that there is a substantial chunk of the school community, often a substantial majority, being catered to by making those decisions.