Undersized tow vehicle? Hmmmm...
 

Its hard to tell from the video, but the truck towing the boat looks to be a 3/4 long bed. Not sure what the boat weighs, but that doesn't seem too out of line. Also says he was doing 50 mph when the trailer started to get out of control. Maybe there was a major trailer failure?

It is a 28' Sea Ray, which is probably 10,000 pounds. If it was a 2500 it is well within its towing capacity. It is probably a 1500. Check out his trailer hitch. It is bent down really bad.

Dry weight is 8,500 pounds, but if you throw in fuel, gear, all the crap that is needed, and a 2500# trailer, you're probably over the weight of a 2500.

Towing capacity on the 2500's is 12,000 pounds with a bumper hitch and 16,100 with a 5th wheel, so he would definitely be close to capacity with a trailer, fuel and gear.