Graham O'Brien

Graham O'Brien lived in Sheffield with his wife Grace and her grandson Ryan Sinclair. He had once worked as a bus driver, still having some friends who worked as bus drivers after he had retired.

Graham once had cancer and met his wife Grace, a chemo nurse while undergoing treatment. Once the cancer was found to be in remission, Graham married her and became her second husband.

Whilst returning home after an unsuccessful session of teaching Ryan how to ride a bike, Grace and Graham were trapped when a swarm of Gathering coils attacked their train in search of Karl Wright, a fellow passenger. He, along with Grace, Ryan and Yasmin Khan, helped the Thirteenth Doctor battle both the coil and its controller, Tim Shaw.

Whilst the Doctor recovered at his and Grace's home, he went around Sheffield to ask if anyone had seen anything unusual. Later, Grace and Graham followed the Doctor's orders to pose as construction managers and evacuate the construction site Karl worked at, so the Doctor, Ryan and Yasmin could rescue him.

However, the gathering coils were still active, with Tim Shaw using them to damage the crane that Ryan and the others were on. Despite Graham's protests, Grace climbed up and destroyed the creature by electrocuting it with live cables. However, Grace was also electrocuted in the process and fell to the ground. Mortally wounded, she died in Graham's arms, after telling him to not be afraid without her. Graham later spoke of how Grace inspired him during their three-year marriage at her funeral and felt guilty that he hadn't died instead.

Sometime after the funeral, Graham helped the Doctor construct a teleporter to take her to her TARDIS. Though he meant to stay behind, he, along with Yasmin and Ryan, were accidentally brought along with her. (TV: The Woman Who Fell to Earth)

Believing the pair to be bonuses in the Rally of the Twelve Galaxies, Angstrom scooped Ryan and Graham out of deep space and transported them aboard her ship.

On Desolation, he found Yasmin and the Doctor, who had been similarly saved by Epzo, Angstrom's rival in what would become the final stage of the rally. The rivals, with the Doctor and her friends in tow, were tasked by Ilin, master of the rally, to race across the planet; the first to reach the finish line at the Ghost Monument would win 3.2 million krin and salvation from planet's hostile surface. The Doctor discovered that the Ghost Monument was, in fact, her TARDIS, phasing in and out of reality. After the Doctor stabilised the TARDIS, Graham entered it for the first time and the Doctor started to take them home. (TV: The Ghost Monument)

Personality
Graham believed if you wanted to know something, you just had to ask a bus driver. He was also wary about rushing into danger. (TV: The Woman Who Fell to Earth)

He was also annoyed when Ryan refused to call him “granddad.” (TV: The Woman Who Fell to Earth, The Ghost Monument)

Graham was compassionate and was greatly distressed by his inability to help Rosa Parks from her destined arrest in 1955, not wanting to be party to such an act. (TV: Rosa)

Behind the scenes
Graham's character profile on the official BBC Doctor Who website, which this wiki does not consider a valid source, states that Graham originally moved to Sheffield from Essex.