One less Challenger in the family

[CudaMoparRay]

Sad about the car but more important glad about your son

[Dakota]

What the heck did he hit that hard that was able to drive away ? 

He had just changed into the lane and was shifting his gaze from over his shoulder to the front view.  All he remembers is seeing the brake lights and then feeling the impact.  No recollection on what he hit, but as you're pointing out it had to be substantial to take a hard hit and keep rolling.