Hi- your sil can contact her state medical board and file a complaint against the doctor. Also, if he is an EMPLOYEE of a medical clinic, the office manager or administration should be notified. Your sister-in-law hired this man to help her, not insult her. If the doctor has a private practice, his office manager should be notifed - and I'm sure her word of mouth criticism will cost him a few referrals.
Pass this along to your sil- if she complains about this doc, she has saved a few patients the trauma and pain she received by seeing this man.