There's only so many times a kid can get sent home from school for biting/kicking/punching before you realize you need some professional help and will do anything to help the poor kid. I wish you luck.
Pi hole devs recommend running it locally only and discourage exposing your pi-hole to the internet. I used pi hole for years but have been using NextDNS lately and it works well outside of my home network, and even has a free tier.