While at first glance it looks like a stupid idea, it's not the worst of which I've ever heard.
IF she has sworn off the credit cards,
and IF she actually needed a new car that can be purchased for 10K (a 4K minivan has some years/miles on it),
and IF the interest rate on the car is less than the interest rate on the credit card bill (that last one's likely true),
then it might turn out to be a moderately decent idea.
And, really, ALL these things must fall in line to make this into a moderately decent idea.
On the other hand, which is probably more likely,
IF she decides to put only part of the money towards the credit card debt and enjoy a little splurge of some type,
or IF the 4K wasn't enough to pay off the credit card bill,
or IF she runs up the credit card bill again,
or IF she goes to the car lot and allows herself to be "upsold" to a more expensive vehicle,
or IF she gets a high interest rate on the car loan,
then she might find herself even deeper in debt.
As things go, ANY ONE of these things could be enough to topple this house of cards she's created.
The bottom line: You can never borrow your way out of debt.