The Prince of Wales, as he then was, did not write a book. He also did not make derogatory comments about disabled matrons, or breach the privacy of teenage grooms. Neither to my knowledge did he describe the private parts of family members
First, Dimbleby quoted from private correspondence and relied on extensive interviews with the Prince of Wales to write the book.
Charles gave unprecedented access to the author and anyone who has read the book knows that it is unquestionably written from a pro-Charles perspective.
Second, Dimbleby wrote that Charles resented Prince Philip, who he saw as a domineering figure who belittled him as an infant, sent him to a school where he was bullied by fellow pupils, and then forced him into a loveless marriage.
Charles also complained that Queen Elizabeth II was a remote figure who let his father handle family matters badly, and the way Diana was portrayed in the book was something any responsible father should have kept to themselves.
Despite clear signs from Buckingham Palace that the book had caused hurt to his family, ie Prince Philip very unusually gave an interview about it calling it “that turgid book”, Charles issued a statement saying he had ``no regrets'' about it.