There is an important message in that that mom may have missed ... that son will not stay on task, is likely disruptive to others, and is not a joy to teach.
The school, as an institution, should do better to communicate the attention issues without humiliating the child, but the mom and the student also seem to have room for improvement. I hope all will take the opportunity to do so.
Good message... poor, poor communication vehicle.
Mainstream public school formats also aren’t for every child.