Story highlights "We're on your side," actor Peter Capaldi tells fan grieving loss of his grandmother

9-year-old Thomas Goodall comes from a home of "Dr. Who" fans, or Whovians

Thomas wrote a letter to Capaldi when he took over role from Matt Smith

The past few weeks have been hard for 9-year-old Thomas Goodall, who lost his grandmother in early October.

It was the first major loss of a loved one for the boy with autism from North Baddesley, England, who relies on a consistent routine to avoid meltdowns, his father, Ross Goodall, said

Things finally began to take a turn for better on Monday, when Thomas received a comforting video message from actor Peter Capaldi, who plays Thomas' favorite TV character on "Doctor Who."

For the first time since his grandmother's death, Thomas smiled.

"I think it probably meant everything to him," his father told CNN. "I think it gave him the emotional support that we as parents couldn't."

After Ross Goodall uploaded the video to YouTube on Thursday for family to see, others took notice and started sharing it, drawing more than 200,000 views in 48 hours.

It didn't come out of the blue. Thomas comes from a household of Whovians, where sonic screwdrivers, robot Daleks and TARDIS time-travel machines make up much of the decor.

The fanaticism extends to Thomas' fashion choices. His signature outfit consists of a checkered shirt, suspenders and bow tie in honor of the 11th incarnation of the time-traveling doctor played by Matt Smith -- one of Thomas' favorite doctors. Other days, he wears a pair of Converse sneakers, 10th doctor David Tennant's trademark look.

When Capaldi took over the role from Smith in 2013, it was a big deal for Thomas, Ross Goodall said. To help cope with the change, Thomas sent Capaldi a letter in September letting him know that he looks forward to following Capaldi's adventures as the new Doctor Who.

Thomas meets former "Dr. Who" actor Colin Baker, left.

Capaldi responded with a letter and autographed headshot. After Thomas' grandmother died, Ross Goodall reached out to Capaldi through his agent and explained that Thomas was having a hard time dealing with the death of his grandmother.

Capaldi came through with the video.

"Thank you very much for your letter. I really enjoyed getting it because, you see, when Clara and I are traveling around time and space, sometimes bad things happen to us. And, you know what, Thomas, sometimes sad things happen to us, too, so it's nice to know that there's somebody like you out there who's on our side, and you should know that we're on your side.

"So you look after yourself, take care and be happy."