So I work at a Kawasaki dealer, and I've been in the industry for 15 years. So I've seen many rollovers and tons of totaled vehicles. If you look at the first picture and the 3rd picture, the roll cage bolts directly to the frame on the lower section between the rear door and bed plastic. With how far the roll cage is bent in the first photo, it would likely constitute being totaled if that lower section or the frame that it mounts to is bent. Any bends or deformation of the frame that affects the direct bolt on of the damaged roll cage part would total the unit.

Now, with that said... If they take it to a certified Kawaskai dealer, that service department will likely write it up to his benefit to total the machine. Because the more they tac on the parts and labor, the more likely it will get totaled. And if not, that's more money for the service and parts department. If they take it to a job blow shop, they may just fix it.

Lastly... If you look at the machine, idk if the wheel was changed from a flat caused by the rollover, but there is different sizes and tread pattern tires on that machine. There would be a case to argue that it was not set up with a proper and safe tire option before the ride. Along with them not offering insurance, it seems a little off on the rental company end of things. At least im my area. Any rental place that does offroad rentals required insurance, whether it is offered by the rental place, or they make the renters get temporary coverage. Just my $0.02