Brian Carroll is the father of Dylan Keogh. At some point after Dylan's birth, he was put in foster care and estranged from his father.
In 2015, he was involved in a car crash with his girlfriend Hazel and they were admitted to the ED, where he was treated by his son. However, it transpired that Hazel was pregnant and he told Dylan that he didn't want him in his life anymore.
By May 2016, Hazel had given birth to their baby daughter Rihanna. However, when Brian parked up his car and left the keys and Rihanna inside accidentally, he was forced to get a brick and smash his car window which resulted in him receiving a deep hand laceration. He was admitted to the ED and treated by Dylan, although neither were happy about it. Hazel arrived soon after and tried to convince Dylan that Brian had changed although he failed to believe her. Dylan later diagnosed Brian with a lung condition as a result of his smoking, and became angry with him when he caught him smoking outside the ED.
Hazel and Rihanna visited the ED in June as she was concerned for Rihanna's health. Brian later turned up and Dylan was furious at the possibility that Brian's smoking had caused it. Two weeks later following a fire at their house caused by one of Brian's cigarettes, he informed Dylan that he'd be leaving them. After this, Dylan offered to help out Hazel with Rihanna.
Behind the scenes
Matthew Marsh portrayed Brian Carroll for one episode of Casualty in 2015, "The Long Haul". He returned for three more appearances in series 30 in 2016. In August 2018, it was revealed that Marsh would reprise his role as Brian in autumn 2018.