Brian Williams (Dinosaurs on a Spaceship)

Brian Williams was the father of Rory Williams, the father-in-law of Amy Pond and paternal grandfather of River Song. When River married the Eleventh Doctor, he became the Doctor's grandfather-in-law.

Biography
Brian attended Leadworth Primary School's nativity play one year in the 1990s when his son was cast as Joseph. He commented that Rory and Amy made a "lovely couple", which his granddaughter agreed with. (COMIC: Imaginary Enemies)

Brian was not present when the TARDIS dramatically materialised in the middle of his son's wedding reception, and was not introduced to the Doctor that evening. (TV: The Big Bang, Dinosaurs on a Spaceship)

Brian and the rest of Amy and Rory's families and friends were under the belief that the couple honeymooned in Thailand (TV: Dinosaurs on a Spaceship) when in fact they travelled through space and time aboard the TARDIS (TV: The Big Bang, TV: A Good Man Goes to War) and honeymooned on an interstellar cruise ship (TV: A Christmas Carol) and on a planet which was on a honeymoon with an asteroid. (TV: Death of the Doctor)

Brian first met the Eleventh Doctor when the TARDIS materialised around him while he was attempting to help Rory and Amy change a ceiling light bulb at their house. The Doctor had taken Rory and Amy along with Queen Nefertiti of Egypt and John Riddell to 2367 to investigate a ship that was headed straight to Earth and would reach it in six hours. Upon entering, they immediately found it contained dinosaurs. The Doctor did not realise that the TARDIS had materialised around Brian and had taken the latter aboard until after the TARDIS landed on the spaceship.

While looking at the main engines of the ship, the Doctor, Rory and Brian were taken to Solomon by his robots. Solomon had killed all the Silurians on this Silurian Ark and forced the Doctor to repair his legs so he could make off with the cargo. Discovering he had a few hours until the ISA launched missiles at the ship and unable to pilot the ark, Solomon took the most valuable thing on the ship identified by his IV system, Nefertiti. The Doctor magnetised the ark, trapping Solomon's ship that was inside. The Doctor released it once he put the signal of Silurian Ark inside Solomon's ship. The ISA missiles destroyed Solomon. Rory and Brian, who possessed the same gene chain, were able to pilot the Ark to safety with the parallel pilot compartments. The Doctor returned everyone home, and gave Brian a sense of adventure when he saw the Earth from space.

Brian began travelling around the world and sending homemade postcards back to his son and daughter-in-law. Among the postcards was one from the planet Siluria, to which he had travelled with the Doctor and the dinosaurs aboard the Silurian Ark. (TV: Dinosaurs on a Spaceship) Brian lived in London, in reasonably close proximity to his son and daughter-in-law's home. He watched and recorded the Shakri cubes during their slow invasion of Earth, and started "Brian's Log", describing any changes. During Amy and Rory's anniversary, he noted their clothes had been different after they ran into the Doctor and realised they had gone on a trip in the TARDIS.

Later, at the time of the cubes' activation, he helped Rory at the hospital. While searching for medical supplies, two "orderlies" took him aboard the Shakri ship. The Doctor rescued Brian, and Rory, who had followed him on board. He restored the millions of humans whom the cubes had put into cardiac arrest, destroying the ship in doing so.

On Brian's urging, the Doctor took Amy and Rory back as full-time companions, as travelling with him was a once-in-a-lifetime opportunity. The Doctor invited Brian back to travel again in the TARDIS with his family, but Brian declined. He said that someone had to tend to Amy and Rory's plants. (TV: The Power of Three)

Personality
According to Rory, Brian disliked travelling to other places; however, following his adventure aboard the Silurian Ark he began travelling quite often and shared his travels through postcards with his son and daughter-in-law.

Brian loved his son, Rory, but didn't seem to have very much faith in him until their adventure with the Doctor. He liked his daughter-in-law Amy and noted that Rory was a lucky man. During the adventure, Brian bonded with Rory and realised that Amy was as lucky to have him as Rory was to have her. Brian was more confused than frightened when the Doctor took them to a spaceship full of dinosaurs, unable to fully believe that it was really happening. Although he did not fully understand what was going on, Brian did show that he was capable of picking up small details, telling the Doctor that he and Rory could pilot the ship after hearing the Doctor mention something about a gene chain. He also displayed delight about getting the chance to pilot a spaceship, finally opening his mind to the fact that what he was experiencing was really happening and not in his imagination. (TV: Dinosaurs on a Spaceship)

When the Doctor returned to Earth, Brian seemed comfortable in his presence and devoted himself to keeping an eye on the cubes at the Doctor's request. He displayed some concern about what happened to the Doctor's companions if they stayed with him for too long, but despite this he encouraged Amy and Rory to continue their travels with the Time Lord. (TV: The Power of Three)

"But not them, Brian. Never them."
In The Power of Three, when Brian asked the Doctor what happened to the people who travelled with him, the Doctor explained that some left him, some got left behind, and admitted that some, "not many but some," died. He then promised Brian, "Never them." In the very next story (The Angels Take Manhattan), Amy and Rory would meet a bitter-sweet fate. Rory was sent back in time by a Weeping Angel, and Amy decided to join him so he wouldn't be alone. They lived their lives together in the past and eventually died in their eighties, some time prior to 2012.

It has not been seen on-screen if or how Brian learned of their fate. This was not originally to be the case, however. P.S. was envisioned as a live action coda to the events of the September 2012 portion of series 7, particularly The Angels Take Manhattan. However, according to its writer, Chris Chibnall, it was cancelled when an actor's availability fell through. Its storyboards were then animated, and narration was commissioned from Arthur Darvill. Ultimately the scene was made public by the BBC as a webcast that was uploaded following the broadcast of The Angels Take Manhattan.

P.S. reveals that a week after Rory and Amy left with the Doctor, Brian, having been watering the plants as he said he would in The Power of Three, answered a knock at the door to discover an American man in his sixties, who gave Brian a letter and walked in. Brian sat in the lounge and read the letter revealing it was from Rory, explaining that he and Amy are alive and well, but stuck; they can't come back. However, he assures Brian that he and Amy had a wonderful life in New York, "fifty years before [Rory] was born," and adopted a son, Anthony Brian Williams, who was the man who delivered the letter to Brian. When all was revealed, Brian went to Anthony and welcomed him with a warm embrace.

Unique status

 * Brian, Rory and River comprise the only example of three generations each flying in the TARDIS. To the extent that Brian is a de facto companion or a companion-presumptive, the trio also constitute the only example of three generations of companions.
 * Brian and Wilfred Mott are the only characters whose selves and grandchildren have each flown separately in the TARDIS, and are two of only four (with the First Doctor and Jo Grant) who selves and grandchildren all flew in the TARDIS. Brian is also one of only four parents (along with Rory, Amy and Jackie Tyler) to have flown in the TARDIS with his or her own child; Sarah Jane Smith and adoptive son Luke Smith were momentarily in the TARDIS together, but it was stationary at the time. (TV: Dinosaurs on a Spaceship, The End of Time, Flesh and Stone et al., The Runaway Bride et al., An Unearthly Child et seq., Death of the Doctor, The Impossible Astronaut et al., Journey's End, The Wedding of Sarah Jane Smith)