40 ILCS 5/8-158

A child's annuity is payable monthly after the death of an employee parent to the child until the child's attainment of age 18, under the following conditions, if the child was born before the employee attained age 65, and before he withdrew from service: (a) upon death in service from any cause; (b) upon death of an employee who withdraws from service after age 55 (or after age 50 with at least 30 years of service if withdrawal is on or after June 27, 1997) and who has entered upon or is eligible for annuity. Payment shall be made as provided in Section 8-125.