Someone who did that and “got off” or almost off will do it or something equivalent again. And again. When there is no perceived consequences the >i>first time</i> then it will be burned into his brain that there are no consequences and getting such a wee sentence is, to someone who knows that what he did is a big deal in the real world, an understanding that he got away with it. If he was on meth or crack when he did it then it is certain that he will do it again.
The power of forgiveness is a powerful thing, that I know from very personal experience on a very personal matter.
I don’t know anything about the kid. Maybe he was so genuinely and abjectly contrite (and not genuinely and abjectly sorry that he got caught, as is usually the case) that the family did forgive him.
I suppose it is possible.