You are right... and I'm doing a very good job of showing why its a good thing I avoid any kind of financeI think you've misread it - I think he meant that if he paid off the £25k loan as he originally intended to, he would have ended up paying £31k back overall when the interest was counted. I'm assuming it was a £25k loan over 5 years at 9.9% = £31486 total repayable or £525pm which is what he mentioned he was currently paying
He's currently got £22k left to pay on the loan and the car is worth about £16.5k on a good day
Still, same options apply all be it with a bit less negative equity.