Sybil serves as an auxiliary nurse and develops feelings for Tom Branson, the family's chauffeur and a staunch Irish nationalist. By the end of the second series, the couple marry and move to Dublin, having finally gained Lord Grantham's blessing. Sybil (now pregnant) and Tom return to Downton after fleeing Ireland in the third series, where Sybil gives birth to a daughter but dies soon after due to eclampsia. Matthew Crawley Matthew Reginald Crawley (played by Dan Stevens) (1885–1921) is a middle-class distant cousin of the Crawleys who becomes the heir to the estate in the first episode and soon after moves to Downton. He finds it difficult to reconcile the traditionalist, aristocratic lifestyle of Downton with his middle-class upbringing, but he is eventually accepted into the family and becomes something of a surrogate son to Lord Grantham. Matthew and Mary fall in love, but circumstances separate them, and Matthew becomes engaged to Lavinia Swire. Matthew is paralysed from the waist down while serving in the First World War, but, after a miraculous recovery and difficulty moving past Lavinia's death from Spanish flu, he and Mary wed in 1920. After a financial scare, Matthew becomes a co-owner of the estate, and begins working on plans to modernise it with the new agent, brother-in-law Tom Branson. In September 1921, Mary gives birth to their son George, but Matthew is killed in a car crash while driving home from the hospital. Following his death, his son George becomes the heir to the earldom, and a letter is found that serves as a will for Mary to inherit Matthew's share of Downton. Matthew dies because his actor chose to leave the series. Julian Fellowes wanted to have Matthew die in series four, but the actor wanted to leave sooner. A Huffington Post poll revealed that 85% of the respondents expressed dislike of Matthew's death. Maureen Ryan of the Huffington Post stated that she believed Matthew's death was beneficial to the story as his storylines had grown repetitive. Isobel Crawley Isobel Grey (formerly Crawley, née Turnbull), Lady Merton (played by Penelope Wilton) is Matthew's widowed mother. A recurring theme during the first two series is the clash between Isobel's more modern and liberal values with the traditionalist ideas of Lord Grantham and his family. Isobel, a former nurse, constantly takes up new charitable causes, helping run the convalescent home at Downton and assisting refugees