Our 2010 Ram rear-ended badly!!!

Last Thursday at 6pm my wife, son and I were rear ended by a 74 year old man with advanced Parkinsons disease. We were at a light and waiting for the light to change when we noticed an argument in the Starbucks parking lot next to the street. A young couple was trying to make the gentleman give up his keys because he had hit their car, (they thought he was drunk by his actions) but he instead got in his car, threw it in reverse and punched it! He cut the wheel hard and went in a large curve accelerating the entire time. He hit two more cars before exiting the lot, and still accelerating, glanced off the car behind us and slammed right into our 2010 Ram. He hit so hard it lifted and pushed the rear of the truck sideways a foot. He was driving a Toyota Rav4 Sport. We saw the entire event unfold and I even had time to put the truck in 'park', and place both feet on the brakes to keep from slamming into the SUV in front of me that had a family in it. We still got shoved into them but nearly as bad. All together he hit 5 vehicles. He was flailing and shaking uncontrollably and no one could understand anything he was saying.
My sons OK, I have some whiplash, but the wife got it bad as she was turned sideways in her seat watching him as he hit us, yelling "he's about to hit us" the milli-second before he did. Over $10,575 in damage overall. The collision shop says the frame is not bent and the truck is new enough and still of value to fix rather than total. However I plan to submit a "diminished value claim" against his insurance because a Car-Fax report will obviously show this and diminish any trade/sale value to the vehicle.