Short answers, pulled from the story.
George Cavendish (1497 to c. 1562) was an English writer and gentleman-usher who served Cardinal Thomas Wolsey from around 1522 until Wolsey's death in 1530. He is historically significant as the author of Thomas Wolsey, Late Cardinall, his Lyffe and Deathe, described by the Oxford Dictionary of National Biography as the "most important single contemporary source for Wolsey's life."
Cavendish served Wolsey as gentleman-usher, a position requiring him to attend the Cardinal at all times and to oversee the lavish entertainments Wolsey hosted. He held this post from around 1522 until Wolsey's death in 1530.
Yes. A manuscript of Cavendish's biography circulated widely before publication, and one copy reached William Shakespeare, who drew on it for his play Henry VIII. The scholar Samuel Weller Singer argued that Shakespeare "merely put Cavendish's language into verse."
The work was first printed in 1641, in a garbled text under the title The Negotiations of Thomas Wolsey. The genuine text from contemporary manuscripts appeared in 1810, and Singer published the first complete edition in 1825 as The Life of Cardinal Wolsey, and Metrical Visions.
George Cavendish was a great-grandson of Sir John Cavendish, the common ancestor from whom both the Dukes of Devonshire and the Dukes of Newcastle inherited the Cavendish family name. His brother William Cavendish was the second husband of Bess of Hardwick and the owner of Chatsworth House.
Cavendish appears as a minor character in Hilary Mantel's novel Wolf Hall, where Thomas Cromwell calls him "a sensitive sort of man." Robert Wilfort portrayed him in the television adaptation. David Oakes played Cavendish in David Starkey's 2009 documentary series Henry VIII: The Mind of a Tyrant.