Family members suing one another is actually much more common than you would think. The reason is because you cannot sue another person's insurance company directly. Often, one family member gets in an accident and another family member has insurance that would cover the injured family member's medical bills and other expenses. However, if you have ever dealt with an insurance company, you know that they will do anything they can to delay and deny paying a legitimate claim. To force the insurance company to pay, the only available avenue is to sue the family member who purchased the insurance policy and then the insurance company has an obligation to legally defend the person and pay any settlement or jury award. Usually the person being sued has no objection to being sued and is very angry with the insurance company for denying the other family member's claim. I don't know the facts of this story, but I am willing to bet a lot of money that is what is going on here. That is why people buy insurance, to cover accidents that happen on their property. After paying the premiums for years and then an accident does occur, the insurance company frivolously and fraudulently denies the claim and forces you to sue your own mother. Anyone want to start a colony on the moon? Insurance adjusters and not invited.