I got a response: (Google translation) If the man wanted to remain incognito - and he was successful - he probably chose a name and a place of residence at random, which had no connection with his previous life. In any case, that would be a logical procedure. And that he has not been identified so far, despite the photo, previous illnesses and internet "popularity", indicates, that he came from a corner of the earth, in which the authorities did not look for him and / or from an environment, in which nobody missed him. There are also German language islands outside of Europe. I do not know how good the hotel employee was in assigning a foreign language accent. Dr. Bergmann's books were made public after 2009 and only 2 were made public circa 15 years before in a smaller edition*. These 2 books' content, which could have been known by our PB, doesn't resemble his own fate. No connection recognizable. * "Dicke Liebe" and "Tore des Bösen"