Two things. First, if you are not familiar, start reading Chump Lady - The Archives (look it up online). There, you will find many divorced parents who have had similar ex experiences.
Two - rage is a common Narc tactic. Your son using rage to get his way and court financial disaster helps no one. (I’m sure he’s a good kid, but as the kid of a Narc, they can mimic some behaviors, no matter how much they also see it as being a bad trait of the Narc parent.)
If your ex co-signs for anything financial, be prepared to be controlled by this. Not good.
You need allies STAT that can present the financials to your kid, and tell them why as of right now, things are bad. If he hasn’t come up with enough money for school without incurring major debt, it’s not your job to do so. “Just want to get away” when he hasn’t put enough skin in the game isn’t acceptable. “Starting over” doesn’t mean going into life-sapping debt.
And you have other kids? You can’t afford his tuition now!
Your kid needs to make this work, not you. If he ruins your credit with his loans, what are your other kids going to do?
Sometimes hitting pause and saying no is the most important way to avoid a calamity.
You need allies in this. In a way, you’re “just mom” to your kid. This debt is not a disagreement over something minor - it has long-term financial implications for you and your son.
Read Chump Lady - so many women have been led to financial ruin by the actions of male family members (and vice-versa). You can’t afford to cave to bad loans.
Find allies to have these conversations with him (not his dad, obviously). He is taking things out on you, when you are the voice of reason. Even if this is all coming in at the last minute, it’s not that uncommon.
You’ve got this.