If you're worried it could come across as an overreaction, it might be helpful to draft your message and get feedback on the content & tone from someone whose judgement you trust.

Having no experience as a parent, I can only throw out some ideas.

Maybe talk to the people who mentioned this to see if they want to figure sth out together? And/or contact the teacher (or other person who might deal with such things) with your concerns - if they seem reasonable/trustworthy.