A: The answer is "it depends." A lawful authorization or subpoena, used in accordance with a legally sound basis, usually subjects the records to disclosure. This is a complicated question, as the release of some records has more requirements than others.
An attorney should be able to give you some guidance without too much effort.
A: This certainly looks like a basis for a legal claim against the teacher's aid and the school or others could very likely be liable as well, depending upon the facts related to hiring and training and supervision of the teacher's aid.
You should post the state where this occurred so attorneys can determine if the jurisdiction is applicable for their legal practice.