Mayor Brad Cole will have 60 days to appoint Jack's successor. Cole said he did not have a successor in mind.
However, under provision 65 CS IL 5/5-2-12(6) of Illinois state law, the council selects the replacement, not the mayor:
(g) If a vacancy occurs in the office of mayor or councilman, the remaining members of the council, within 60 days after the vacancy occurs, shall fill the vacancy by appointment of some person to the office for the balance of the unexpired term or until the vacancy is filled by interim election under Section 3.1‑10‑50, and until the successor is elected and has qualified.
The council may choose to leave the selection up to Mayor Cole, but it is not automatically his decision