I can't imagine the King would deny his brother the opportunity to make himself useful on the estates in a private capacity. If I remember correctly, it was after the Duke of York's forced retirement that the then-Prince of Wales accompanied him to a private church service. The then Prince of Wales, along with the Queen, also responded to every "leak" of the Duke of York's wishes to return to public life with statements of his personal support along with the refusal to restore him to a public role. Over the past week and a half we have seen that the King allowed the Duke of York to participate in all parts of the family's public mourning, even the nonessential walkabouts. In short, the indications are that he has not been treated at all harshly within his family. If the Duke of York never works out a means of supporting his King and Royal Family while remaining outside the public eye, that would most likely be his own choice, not the King's.