It is a disgraceful story. As has been noted that surface irregularity is hardly a pothole, and the kid's other issues are utterly irrelevant. My guess is he was pootling along, heedless, feckless, no hands, and came a cropper like the idiot he must be. I cannot imagine any other way of crashing on that little bump in the road. I ride over that kind of stuff all the time on a road bike without a second thought.
Sadly I expect some legal aid lawyer will get them something for it, although I hope not.