He might now have a mismatch between the sizes of the new rotors and his existing unit bearing hubs. Jeep changed the size of them in mid-1999 so depending if his TJ is an early or late 1999 model he might have gotten the wrong rotors.
The unit bearing hub changed dimensions as shown here... measuring it to see if he has an early or late unit bearing hub will tell him if he needs rotors for '97 to early '99 or 99.5 or newer rotors. If they're mismatched the brake will bind.
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