For real, this is stupid. They going to start charging kids with threats on FB, snap, ig? Legally they could. If the kid makes a threat to the other kid and he or his parents say "yes, I want to press charges." That's it. But I doubt the kid or his parents were asked if they wanted to press charges over a diss track.
If we were a civil country intervention would be good. Maybe the authorities would meet with both kids and parents and have them talk and squash it. If that kid really got beat up is the other kid getting charged? Or do they not have enough evidence? This whole thing is weird.