if the doctor is blatently lying then i think you should express your concerns to your parents, because as Elle said, you can be prosecuted if you do not alert the correct people to your change of circumstances.
i know you didnt wright it, and there isnt really anything you can do apart from talk to your parents and sister and ask them whats going on. it does show how much of a good person you are by wondering if this is right though, well done for that, most people would just ignore it and keep things simple and easy
Hannah X