755 ILCS 6/20-45
Testimony or other evidence at a hearing for formal proof of a will under Section 6-21 of the Probate of 1975 by a remote witness who witnessed the will under Section 15-20 shall establish the testator and remote witness substantially complied with the requirements of Section 15-20 and the remote witness believed the testator to be of sound mind and memory at the time of the signing. Formal proof of a will signed under Section 15-20 does not require testimony or other evidence that the remote witness attested to the will in the presence of the testator. Testimony by the remote witness that conflicts with a statement in the attestation clause or affidavit that the remote witness attested to the will in the presence of the testator does not affect proof of the will or the credibility of the remote witness.
755 ILCS 6/20-45