40 ILCS 5/15-147
A child is deemed dependent upon his or her natural or adopting father or mother if the child is living with or receiving support from such parent. If the child is not living with or receiving support from such parent, he or she is deemed dependent upon that parent if the child (1) has not been adopted by some other individual, and (2) is not living with or receiving more than 1/2 support from his or her stepparent.
A child is deemed dependent upon his or her stepfather or stepmother if the child is living with or receiving at least 1/2 support from the stepparent.
A parent is considered dependent if receiving at least 1/2 of his or her support from the participant or annuitant at the time of the death of the participant or annuitant.
40 ILCS 5/15-147