10 ILCS 5/23-23.1

No election contest shall abate on account of the death of any contestee in such contest.

Upon the suggestion of the death of any contestee by the contestant at any time before final judgment, within five days thereafter any elector of the State or political subdivision thereof for which the contestee was declared to be nominated or elected, may appear and intervene in such proceeding, or in case no elector appears within such five days, the court shall appoint such an elector to appear and intervene in such proceeding, and defend the same and thereupon the court shall proceed to final judgment.