First of all, glad the kid was not hurt to seriously.
Second, he should have been wearing a helmet.
Third, it was obviously his fault, but of course you feel bad for it happening, who wouldn't?
It was good that the father pointed out the kids fault in it and did take some of the responsibility himself.
Hopefully this kid learned a valuble lesson.
Was this at night when this happened? You mention dark clothing, etc, thats why I ask.