I just wanted to say that IF the whole point of this exercise was to figure out how to get your kid to work within a budget, without YOU having to dirty your hands by issuing the budget, then you need to think bigger picture. The kid may have some minor resentment about a budget (especially if this is a kid unaccustomed to being told “no”), but relying on hope and a trail of breadcrumbs is a recipe for resentment.
When your kid picks the expensive school anyway, and you wont say no? Leads to resentment from you & wife when your loan balances pile up.
When your kid picks the expensive school anyway, and you pull the rug out from under him and say “no” at the last minute? More resentment from your kid than if you’d given a budget in the first place.
When your kid picks the expensive school, you don’t say no, and you can’t pull off the same financing for the second kid? You’ll resent the 1st kid, and the 2nd kid will be mad at everyone involved.