That's absolutely true, you should have honored it. But if it doesn't matter what he said why have you used it as an excuse for your actions?

I'm not saying that it becomes his fault the second he said not to do it, but it certainly would make you less evil in the eyes of your Aunt/Uncle.

But you have made that clear that you don't want him involved and that's your call. Help them move/rent them something to get their stuff from one place to the next. Work out some type of payment system to work towards paying them back what the SUV was worth. You were in a rough place and people make mistakes, as long as you get across that you care about them and want to take steps to make things right they will understand.