Setting: Present-Day Germany
Character: A teenage boy, approximately 14 years of age.
This is fanfiction, and the fandom involves many strange and paranormal goings-on within the town. This boy's problem is related to these goings-on, but right now his friends don't know what to think and have taken him to the doctor because he was complaining of strange pangs in his heart (which are also related to the paranormal, as will be explained later) and then collapsed. When he awoke, he no longer remembered anything about his identity and instead insisted he was a knight of legend. He also wants to leave, which the others have only managed to temporarily prevent by convincing him to see a doctor.
The doctor won't find anything wrong with his heart, or anything physically wrong at all, but I'm assuming he'll get diagnosed with the kind of amnesia that comes from an emotionally traumatic experience or dissassociative fugue. The only possible clue as to what could have caused this is a terrifying dream of being killed he had right before his heart pained him the first time. (As mentioned, in actuality it was something paranormal, but the doctor wouldn't be diagnosing that, haha.)
My question is, How would the doctor tell his friends to talk to him? Would they have to humor him and go along with his insistence that he is a legendary knight, or would they need to keep insisting his true identity and try to get him to remember?
Searched terms: "how to talk to someone in a fugue state", "how to talk to someone with amnesia", "fugue state"; looked at the Wikipedia article for "fugue state".