Floyd VanHooser said he lied to police because he was mad at Bernie Fine for not hiring a lawyer to fight his criminal conviction.
Fine helped raise the 56-year-old VanHooser after his parents died.
Syracuse University fired Fine in late November after two other men accused him of sexual abuse. He had worked for the school for 35-plus years.
Fine, 66, has denied wrongdoing and has not been charged. Fine's attorney, Karl Sleight, declined to comment on Sunday. A federal investigation is ongoing.
The Associated Press contributed to this report.