It'd be fine if he were moving it around his property. Not fine at high speeds on the highway. Just because a truck isn't squatting, doesn't mean it's handling the load. OBS Chassis and suspension can not safely continuously control that much weight, and in an emergency situation OBS brakes will not be able to bring that load to a stop.

Modern 1-Tons actually rated to tow that kind of load have much stronger frames, larger axles, and literally double the braking power on just the front wheels alone.