Short answers, pulled from the story.
William Brereton was born around 1487 or perhaps as late as 1501 to Sir Randle Brereton of Ipstones, Shocklach, and Malpas and Eleanor Dutton. Records suggest he may have been born as late as 1501 to align with the birth of his younger brother Sir Urian Brereton circa 1505.
By 1521 William Brereton held the position of groom of the king's chamber and from 1524 he became groom of the privy chamber. His roles included Escheator of the county palatine sheriff of Merioneth and Flint constable of Chester Castle stewardship of Longdendale sergeant of the peace and steward of Halton.
Thomas Cromwell masterminded proceedings against Anne Boleyn and her co-accused including William Brereton to end his control of the Welsh Marches. There was never indication he was a close or intimate associate of the queen and what sealed his fate was political expediency rather than evidence.
On the 17th of May 1536 five men including William Brereton walked from the Tower to a scaffold on Tower Hill where they were executed. The sentence was later commuted to beheading instead of hanging drawing and quartering after all four men received sentences for high treason adultery with the queen and plotting the king's death.
Modern scholarly consensus holds that Anne Boleyn Brereton and co-accused were innocent as no witnesses testified against him during the trial process. Historian Eric Ives produced a seminal biography shifting focus from common law to Tudor history while academic books portray Brereton based on factual evidence rather than fiction.