In real life, Adams and Jefferson had resumed their friendship through correspondence while Abigail was still alive.
While they're waiting for Nabby's surgery to finish, Abigail tell her nervously pacing husband, "For God's sake, John, sit down." This is also the first line of the 1969 musical "1776," in which John Adams is the central character.
Nabby's diagnosis and surgery are depicted as both occurring on the same day in 1803 at Peacefield in Quincy, Massachusetts, by Dr. Benjamin Rush. In reality, Nabby was diagnosed with cancer in 1810 but the surgery was not performed until October of 1811. The surgery was not done by a solo Benjamin Rush as depicted in the series, but Dr. John Warren with a team of surgical assistants brought along to help him. Dr. Rush was a Pennsylvania delegate to the Continental Congress in Philadelphia in 1776 and a signer of the Declaration of Independence. At the time of the surgery shown in the series (1803), he was serving as the treasurer for the US Mint in Philadelphia, three hundred miles from where the surgery was performed in Massachusetts. Dr. Warren, the surgeon who actually performed the surgery in 1811, was a well known physician in the Boston area, a graduate of Harvard, and had served as an Army surgeon in the early revolution battles around Boston such as Bunker Hill.
Last episode of the series.