‘Bridgerton’ Season 4 delivers devastating twist involving Francesca's husband Lord John Stirling
The second part of 'Bridgerton' Season 4 is finally here, with the ultimate batch of final four episodes. While the Benedict Bridgerton and Sophie Baek love story continues to take centre stage on Netflix's Regency-era drama, several secondary characters step into the spotlight, serving as expressions of the show's superbly crafted character arcs. This story contains Season 4 spoilers.
The sixth and seventh episodes of Season 4 saw the tragic death of Lord John Stirling, the Earl of Kilmartin, played by Victor Alli. The entire family mourned his passing away, and the subsequent fate of his widow, Francesca, remains uncertain. Although Season 4 foreshadows John's death earlier in the preview trailers, it does not dwell on the cause of his death. It is described that John passed away from a 'headache,' and it is possible that the real reason behind his untimely passing wasn't very well understood in the era in which the show is set.
The very depiction of Francesca and her relationship with John is one of the few instances of the Netflix show deviating from the source material novels written by author Julia Quinn. The book 'When He Was Wicked,' which is widely considered to be the one that focuses on Francesca, explained that John succumbed to a case of ruptured cerebral aneurysm, which is diagnosed by the presence of a bulge either in the weak spot of an artery or around the brain. The symptoms include nausea, headaches, seizures, and vomiting. A rupture of the bulge, though rare, can be fatal. 
Appearing on the Ton in Season 3 of the Netflix show, Francesca developed an unlikely connection with John. This eventually led to their marriage and their settling down at his London home by the beginning of the present season. Hannah Dodd, who plays the character of Francesa, recently sat down for an interview with the Los Angeles Times, during which she described her character's reaction to John's death and the relation it bears to the source material.
Dodd explained, "People who have read the books understand that none of what they’ve seen so far happens in the books. You don’t get to see her on the marriage mart. In Chapter 1 of her book, John dies, and her story starts after that." She further added, "John’s alive for about 10 pages of the book and then there’s a time jump, so we’re not spending a ton of time in what her immediate grief feels like, but it’s enough that we had some clues from Julia Quinn about how she might react.”
In the books, Francesca spends a long time as a widow in mourning before eventually marrying his cousin Michael. The latter subsequently inherited the title of the Earl of Kilmartin. The Netflix show brought about a change in this regard when it changed Michael's character to Michaela. It remains to be seen whether Francesca and Michaela shall develop a connection of their own. All episodes of 'Bridgerton' are now streaming on Netflix.