Babsi's stepfather

I read the book numerous times and recently saw the film for the second or third time. For half of my life I have been wondering who was the pianist that took over Babsi's custody. In the book he was described as 'world-famous', with Babsi and Christiane stumbling upon his records in a record shop they visited. I know Babsi's surname was Döge, but I never found anything about any pianist with this surname. I asked a friend of mine who is German to try googling it for me using German phrases, but she was not successful, either. Do any of you know anything more about this person?