Doctor patient confidentiality laws. What is "going too far"?

A friend of mine has a sickly child. Its not a temporary sick, but something that will haunt this child for the rest of their life. Briefly, the child takes medicine in the am and it makes them very tired and move slowly. After the meds kick in and the sickness is not so bad, she goes to school. Everyday. The child makes decent grades. The mother of the child got a letter from the school stating that the child had a lot absences. That was untrue, she had a a lot tardies, but DID in fact go to school. The counselor has called childrens services on the mother and have stated that she is unfit due to the tardies. So, the last time the mother took her child to the doctor, she got an excuse from the doctor stating that what the child was going through was excusable and expected. So when the mother turned in the doctors note to the principal, that should have been a done deal. They school should have recognized the childs disability. After she dropped the doctor note off, the principal called the doctor and told him the students grades were all F's. That was untrue. She is a B student at worst. The principal then told the doctor and the parent that the doctor note was not a valid excuse. How many laws were broken during this little episode? I was curious. I dont have kids and really dont know who to ask. Has anybody else had this kind of experience? It is insane.