did they die intestate? a proper will generally would determine who gets how much. the tax laws would then determine how much of that portion goes to the state. if there is no will, the disbursement depends on a variety of things all different based on the state rules. is there a wife involved, it may, intestate, mean it all goes to her. even if she was not the children's mother.
the rules are deliberately confusing so you have to hire a lawyer. they were written by lawyers to ensure their livelyhoods.
ah, gladstone beat me to it. i see in il. the child might get some in any case. note the lawyer talk to make it unintelligible to mere mortals.