yes all gladiators are. but not sure how a trailer brake module would engage another vehicles brakes. That's why they are called trailer brakes modules, cus, its for trailers. other than that, what you can tow will be based on how your gladiator came built. towing capacity on a gladiator can range from 4000lbs to 7650lbs.
What Puddlejumper says above... PLUS, most vehicles being towed flat-four need to have a Brake Buddy or similar brake actuator installed in the driver's floorboard of the towed vehicle. The brakes on the Gladiator won't be connected to the towed car/truck in any way, unless you're towing the vehicle on a car trailer.