This is not the first biography of the son of Wilhelm I and father of Wilhelm II. Friedrich III, married to Queen Victoria's eldest daughter, Vicky, suffered from throat cancer, and reigned for only eighty-eight days.
I am aware of two other biographies published in English. The scholarly Frederick III Germany's Liberal Emperor (Greenwood Press: 1995) and John van der Kiste's easy-reading Frederick III German Emperor 1888 (Sutton: 1981)
John van der Kiste has also written a two-act drama based on the Emperor's illness, which is available in a Kindle edition.
John van der Kiste also wrote Dearest Vicky, Darling Fritz (Sutton: