Supervisor failed to put his discpline notes in employee’s file: What do we do?

Q. We have an employee who has been filing retaliation and discrimination claims against us for over a year. We’ve been able to maneuver the blows so far. But this time he claimed his supervisor falsified all the information in his supervisors log -- his attendance, FMLA, disability records -- and now he requests his personnel file. We told the employee that he has nothing in the file.  How can we prove the write-ups the supervisor put in his daily log truly exist if the supervisor never sent the information to the employee’s personnel file, which is empty. Do we fire the supervisor? Or how can we transfer his information and put it in the file, even though we have already told employee he has no file?  – Win, Indiana