The NY Times has a column by a pediatrician discussing what to do when a middle schooler tells you something he doesn't want shared with parents. It is likely that this will come up at some point in your ministry, and so it is important that you are prepared in advance for how to handle it. This column provides an opportunity for your wellness team to discuss the issue in advance so that you will know what to do when it happens.
And he was horrified. He shook his head vehemently and asked me please not to interfere, and above all not to say a word to his mother, who was out in the waiting room because I had asked her to give us some privacy.
He wouldn’t have told me this at all, he said, except he thought our conversation was private. The situation at school wasn’t all that bad; he could handle it. He wasn’t in any danger, wasn’t getting hurt, he was just a little lonely. His parents, he said, thought that he was fine, that he had lots of friends, and he wanted to keep it that way.
http://www.nytimes.com/2008/12/09/health/09klas.html