I'm under the impression he also plans to load down the ZJ with various things they'll be moving, and even at 6200lbs, he's over his tow capacity by more than 1000lbs, and even that is rated with an empty vehicle.
I would not tow that load with that tow vehicle. Not safe for the driver, the cargo, or the vehicle.
1998 Grand Cherokee 5.9 Limited
2016 Wrangler Unlimited Sahara Edition
Signature rules are dumb