Bert, I agree with Ketan on that it seems like a case of lack of understanding...even though you may feel that you spent a considerable time explaining it. I'd say the first thing is to take one more try to discuss it with them.
In many states, physicians are required by law to report suspected child abuse. I don't know about Maine's laws. The key question is "Is this child abuse?" If you feel it is, I'd suggest reporting it. You may be told that this does not constitute child abuse. Ok, no foul. They won't act. If it IS, then you will have helped the child. In this particular case, I'd say make the report, or at least call the appropriate government office and ask.