While the claim itself seems a bit hard to prove true, ChatGPT cannot exiast outside of technology so it cannot aid patients, the question of if it could pass a medical licensing exam is a bit different. ChatGPT utilizes knowledge from its entire databse to improve itself and therefore does have very good bedside manner and can have medical knowledge. An article by CNN explaisn that ChatGPT cannot replace doctors and even says so itself. If you ask ChatGPT if it could take the role of a doctor it responds," While I am a language model that has been trained on a vast amount of information, I am not a licensed medical professional and I am not capable of providing medical diagnoses, treatments, or advice." So I think it is fair to say the claim that ChatGPT can replace doctors is false but the question of if they have bedside manners or some database medical knowledge could be true.
https://www.cnn.com/2023/04/28/health/chatgpt-patient-advice-study-wellness/index.html