Re: "killer" 4 years old
If the kid's parents own their own home they undoubtedly have homeowner's insurance. People think of their home owner's insurance as covering their dwelling from fire,etc. but there is a liability component that covers (up to what ever the policy limits) injury, to another, negligently caused by anyone in the homeowner's family that resides there. The negligent act need not occur on the homeowner's property (note that the homeowner's policy always excludes injury caused by motor vehicle....thus the insurance company gets to sell you another policy).
When I used to handle personal injury cases I once represented a guy who had been shot in a hunting accident by a 16 year old boy (he admitted that he shot at the "sound" of the "deer" walking through the brush) I told the client that he was s.o.l. unless the kid's parents owned a home. They did and he was compensated by their home owner's insurance.
Since 99% of cases like this are handled on a contingency fee basis I have to think that only a damn fool would sue a 4 year old w/o insurance. I'm not suggesting the suit isn't stupid, I'm just pointing out the fact that a 4 year old having no assets isn't necessarily determinative of whether the lady's estate ever collects a dime.