Startling statement from a doctor.
You know when a judge uses the word 'surprising' and it means shockingly bang out of order. /That/ kind of startling.
This is how homoeopathy came to be popular.
Placebo effect + reversion to the mean = 'It worked for me'
A doctor specialising in a particular condition due to personal experience is one thing. There are pluses and minuses - increased awareness of the patient experience may improve their empathy in dealing with patients, and dedication to their study vs potential to over-identify with patients, have an emotional response when they need to be objective, and possibly weight symptoms that match their own experience over than those that don't.
Going in up front assuming that your personal experience leads to you knowing better than medical studies would surely constitute a serious breach of medical ethics. Can this person be reported to a professional body?