40 ILCS 5/15-191
If any benefits under this Article become payable to a minor, the board may make payment (1) directly to the minor, (2) to any person who has legally qualified and is acting as guardian of the minor's person or property in any jurisdiction, (3) to either parent of the minor or to any adult person with whom the minor may at the time be living, provided only that the parent or other person to whom any amount is to be paid shall have advised the board in writing that such amount will be held or used for the benefit of the minor, or (4) to the trustee of any trust created for the sole benefit of the minor while that minor is living, provided only that the trustee of such trust to whom any amount is to be paid shall have advised the board in writing that such amount will be held or used for the benefit of the minor. The system shall not be required to determine the validity of the trust or any of the terms thereof. The representation of the trustee that the trust meets the requirements of this Section shall be conclusive as to the system. The written receipt of the minor, parent, trustee, or other person who receives such payment shall be an absolute discharge of the system's liability in respect of the amount so paid.
40 ILCS 5/15-191