YouTube Star Caleb Bratayley Mourned in Livestreamed Memorial Service

— -- Caleb Logan Bratayley, the young YouTube star who died unexpectedly from an undetected heart condition, was remembered tonight as a witty, athletic, sensitive boy who loved sushi, magic cards, history and travel, and who touched so many people during his short life.

His family –- who run the popular YouTube channel “The Bratayleys” -- wrote over the weekend that Caleb had died on Thursday. He was 13.

The family -– which doesn’t publicize their actual last name –- held a memorial for Caleb tonight which was livestreamed on Facebook.

During the approximately hour-long event, a video montage featuring moments from Caleb’s life played, after which his coaches, a colleague, a longtime family friend and cousin spoke glowingly about him.

As many as 40,000 people watched the Facebook livestream, with viewers expressing a constant flood of grief and well wishes for the family.

One of the speakers at the memorial identified herself as Paula, a family friend. Standing at a podium beside which was a large photo of Caleb wearing a baseball uniform, Paula described how Caleb had become friends with her son and daughter. He spent time with her family, enjoyed her waffles, taught her about sports, had “a sweet, sentimental side,” and was very funny, she said.

She recalled one day when she was driving and he was with her in the car.

“He says “Miss Paula ‘I have hair’ …. in places I shouldn’t have hair.’ And he said ‘just thought I’d tell you,’ and he gets out of the car and he runs into the house. That’s Caleb,” she said, as laughter erupted.

Three coaches also had lots of praise for the young athlete. One of them, who said he was coach Daniel, said Caleb had innate skill.

“Win, lose or draw, he hit the field with the same intensity and drive. He was every coach’s dream player,” the coach said.

Off the field, Caleb was funny and unpredictable, he added.

“He was so fun. He was easygoing. He never asked for anything. He just went along with the flow and his smile was definitely contagious. He could light up a room,” Daniel added.

A woman who identified herself as Paige, Caleb’s cousin, said she had spent time traveling with the Bratayley family recently.

“He was like a little brother to me,” she said. “He loved life and enjoyed every little bit even if it...We went to Australia and everywhere we went he would find sushi. He liked magic cards -- magic trick cards. He started collecting them.”

All the speakers commended Caleb’s parents -– Billy and Katie -– for raising such a fine family, and they offered their prayers for the pair and for Caleb’s sisters, Hayley and Annie.

The livestream ended before Caleb’s immediate family spoke. An officiant said the family would be spending private time together.

In a Facebook post, the family said it decided to livestream the service “due to an outpouring of support and people’s hope to be part of his memorial.”

After his death, Caleb’s his parents told ABC News that the family has a history of "hypertrophic cardiomyopathy," a heart condition where the heart muscle "becomes abnormally thick," according to the Mayo Clinic.

The disease can go undetected and people suffering from hypertrophic cardiomyopathy "have few, if any, symptoms," the Mayo Clinic adds. But the disease can result in heart rhythms that are abnormal, which can be serious if not deadly.

The family wrote over the weekend on Instagram, adding that Caleb’s death had “come as a shock to all of us. Words cannot describe how much we will miss him."

Caleb's final video for the family page, which has more than 1.6 million subscribers, features the young star pondering what he'd ask his future self. The family also shared a montage of Caleb and his two sisters in a clip titled, "Caleb, Gone But Never Forgotten."

The clip contains moments from a docu-series Caleb and his family were making with ABC News-Lincoln Square Productions about the American Revolution and the 2016 presidential race.

The Bratayleys are associated with Maker Studios, a Disney-owned digital company. Disney is also the parent company of ABC News.