Perhaps your family would not have sued her friends, but when the insurance company goes to recoup their money they go after whomever they can find. In a perfect world, greed is never the motive for a lawsuit. It is only to recoup expenses caused by negligence or malice. (IANAL)

I was involved in a wreck once where two bystanders proceeded to help the kid who hit me out of his car. I was kinda busy with 911 at that moment (and kinda dazed), or I'd have told them to leave him the hell alone. Punk later tried to get my insurance to pay for his pain and suffering. Fortunately in my state they tend to hold you alone responsible when you choose to rear-end someone.