I think its more of an issue that a lot of parents are too lazy to be tough and follow through with disciplinary action. They want to be more like a friend and not a parent. Bad move.
Just because she took the keys to take the car for a joyride doesn't prove wreckless intent. Especially if she had never done that before.
I think that a settlement would depend on how much insurance coverage they have and whether the kid has a prior history.
My girls know that just because they are adults they can't do anything they want because they still live under my roof. Once they move out, then I don't have as much influence in their decision making process anymore...or the Liability.
Even though she is a legal adult at the time of the incident the parents knew that she has mental dysfunction (in other words she's just a "bad-boyfriend" away from making adult films with their Surname).
With that in mind they should have made more of an effort to "lock" or hide the keys to the "4 wheel missile".
If that was my child I would have classify her as "Retard" and make life adjustments and accommodations that reduce or eliminate the liability to society as a whole.
i have NO sympathy for that family since the parents didn't appear to have made ANY adjustments for the welfare of other's safety.
Good thing she didn't run over a herd of kids at a school bus stop. i doubt that there would be any settlement in the works since they would be busy getting their ass from being burned at the stake when they are reminded that they knew about their daughter's "issues" and didn't "adjust" for it.
Oh, and the folks knew that she did coke at least once. Didn't look like she had very good parenting that she did it the second time (that anyone knew about).