Definitely visit him regularly and see what progress you can make. Both shepherds and Danes can be very, very people-sensitive. Our our Great Dane Gracie would just shrivel up as small as she could if you scolded her, but I suspect she wouldn't have noticed if you clubbed her with a baseball as long as she thought you were happy to be with her.
He may be a challenge, but so completely worth it - read my post above about "Princess" - who did eventually become a sweet as pie big galoot, and she came from worse circumstances.
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