HIMYM Cast Had Fundraising Parties on Set After Co-Creator’s Son Was Diagnosed with Rare Disorder. It’s Now a Fan Event (Exclusive)

The How I Met Your Mother community is powerful, to say the least.

When series co-creator Craig Thomas’ son Elliot was born with a rare genetic disorder during the show’s earlier seasons, the cast and crew came together in a big way. Turning pain into purpose, the group used the show’s soundstage to host music-filled fundraising events, benefitting related research.

In the years since the show concluded its nine-season run in 2014, the fundraising effort has been opened up to the iconic sitcom’s fandom through a live charity concert where Thomas and fellow co-creator Carter Bays perform How I Met Your Mother songs with their band, The Solids. Its third annual event took place on Saturday, Jan. 11 at The Bowery Ballroom in Manhattan’s Bowery neighborhood, and featured participation from some of the former CBS series stars.

Now, Thomas tells PEOPLE exclusively exactly how the legen-wait for it-dary phenomenon came to be and the importance of Dr. Paul Grossfeld’s ongoing research.

“Between years two and three of How I Met Your Mother, my son was born, and to our shock, without having known anything in utero, he had this rare syndrome, my son Elliot, called Jacobsen syndrome,” Thomas, 49, tells PEOPLE exclusively of his son’s condition. “It’s a deletion, a little piece of one of the 11th chromosomes missing. The fact that that’s missing has all these different ramifications—health ramifications, developmental ramifications—and again, it was a complete curveball.”

“We thought we had a healthy baby coming out and we didn’t,” he says.

Thomas’ son Elliot, whom he shares with wife Rebecca Alson-Milkman (and the couple also share a daughter named Celia), needed to undergo open heart surgery at just two weeks old when he was “weighing about three and a half pounds,” the screenwriter recalls.

“Then, we were told by the geneticists he’ll have long learning issues, he’ll have delays. It’ll be this journey you did not know you were signing up for. We felt so lost,” he continues. “This is while I’m about to go from the end of season 2 into running season 3 of How I Met Your Mother, feeling so lost. I felt I was living a drama while writing a comedy. And the truth is, they both go hand in hand. We did that on How I Met Your Mother.”

“Honestly, I think the drama of Elliot’s birth in between years two and three [of] How I Met Your Mother informed how the show got more dramatic and emotional in certain ways,” he shares. “Even though we didn’t literally talk about it, ‘Do a storyline about Elliot,’ or anything like that, the tone made its way. Sometimes, How I Met Your Mother is called a comedy that is very emo. I think there was real emo stuff going on in my life that informed things. The whole writing staff was so with me on that journey, and it just made its way into the room.”

Noting how one can “feel so lost and hopeless when these things happen,” Thomas says: “We were just in the dark, wandering around a dark cave. And then, like a little light, a little candle got lit, and that was Dr. Grossfeld. We found him online. He’s the only doctor researching Elliot’s specific condition in America. He is the person doing the research, publishing the papers, finding out how to treat and support and help these children, and saving lives in so doing.”

Dr. Paul Grossfeld, whose research was being spotlighted during The Solids’ Jan. 11 concert (and proceeds from the event benefitted his ongoing work), has “made enormous progress” over the last several years, he reveals.

“The cause of congenital heart defects is not known, even though we think it’s mostly genetic, but it’s largely unknown,” says Dr. Grossfeld, who currently works within the pediatric cardiology lab at Rady Children’s Hospital-San Diego.

“My thinking is if you understand the cause and the mechanism, you can come up with better treatments and maybe, even eventually, get good at it,” he explains. “[In] my first month of training in cardiology, I was taking care of a child because of his heart defects, and he happened to have a rare chromosomal disorder called Jacobsen syndrome. This was in the 1990s.”

“I basically postulated that there must be a gene or genes in that region that’s lost. That’s the cause of these heart defects, not necessarily just in the kids with Jacobsen syndrome, but in the broader population of the 1% of all people that are born with heart defects,” he continues. “And so, that was the beginning.”

Thomas points out that it’s “hard to find funding for research for rare syndromes,” but that hasn’t stopped him and Dr. Grossfeld’s fight, which was commemorated in a big way on How I Met Your Mother‘s legendary Los Angeles-area set.

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“After a few years of knowing Paul, and as I got older, I said, ‘What if we use the support of the How I Met Your Mother community and fandom and find a way to enlist their help to support Paul’s work,'” Thomas recalls. “At first, that took the form of, we did these two very big fundraisers on [the] How I Met Your Mother soundstage on the Fox lot. Stage 22 on the Fox lot. These really big parties.”

For the occasion, the set would be decorated accordingly and the show’s producers, who Thomas says would “find little ways to get money and get free things from vendors and to get this or that. So much of it happened without my having to work hard on it.”

“It just felt like using our little wonderful universe we had all created to do something good. It was absolutely joyful,” he continues. “And for me, my son was still so young at that point. It just felt like everyone coming together to help [during] a hard time I was going through and help do something good for the people that are trying to help kids like my son. So I would leave those events and just cry for an hour out of sheer gratitude.”

Regarding the experience as if they “were shooting another small episode that was called ‘Raise Money for Dr. Grossfeld,'” the Emmy nominee also remembers how “all the cast, and a lot of the guest cast, everyone would come out. We’d have 300 people on that stage partying until 2:00 in the morning. We raised hundreds of thousands of dollars in one night, but then the show ended and I moved here [to New York City]. And I don’t have a big hit TV show going anymore.”

Yet, that wasn’t the end of how Thomas and the How I Met Your Mother community would continue to raise proceeds in support of Dr. Grossfeld’s research. The “new idea” proved to be a winning one, resulting in increased awareness and subsequent funding for a good cause.

“How I Met Your Mother fans are so amazing and the love for the show has extended beyond anything I could have ever hoped for. I’m so grateful to them,” Thomas begins.

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“We said, ‘What if we can play the music of the show?’ Carter [Bays] and I met, my co-creator of the show, Carter, we met by playing in bands in college. So we’re like these frustrated wannabe musicians, and we wrote all the stupid songs on How I Met Your Mother, Robin Sparkles, all the ridiculous songs, we wrote them. And then, we put all these really good songs on the show that we didn’t write that are by real bands. And we said, ‘What if we play a mixture of the silly songs and the actual good songs and we do a night like that, and we make it a night to raise money for Dr. Paul’s research since it’s so in need of support, and we asked the How I Met Your Mother fans, who are the best fans in the world and have been there for us like family, to come out and support this cause?’ So, that’s what we’re doing.”

The Jan. 11 show marks their third event of its kind. Having previously been in a smaller yet still iconic N.Y.C. venue, Mercury Lounge, the charitable event’s 2025 edition was held at The Bowery Ballroom. It was a sold-out affair.

How I Met Your Mother alums Josh Radnor (Ted Mosby), Ashley Williams (Victoria), Will Forte (Randy Wharmpess) and J.P. Manoux (Not Moby) were on hand to sing songs from the acclaimed sitcom with Thomas and Bays’ band, The Solids. “Let’s Go to the Mall,” “Super Date” and “Cat Funeral” were among the songs performed by the gang. Thomas’ son Elliot even hit the stage to lend his drumming skills to various songs.

For Radnor, choosing to continuously partake in the charitable event is a no-brainer.

“I love Craig. There’s ways to love your friends that are more obvious, and then there’s other ways to love your friends. I just feel like this is an act of love for my friend. I remember so well what it was like when Elliot was born, and Craig talking so lovingly about Paul,” Radnor, who recently released his second solo record, Eulogy, Vol II, tells PEOPLE.

“I remember hearing something on NPR years ago. A woman was talking about [how] her husband had some degenerative kind of brain disease and she said, ‘No celebrities have this disease and no celebrities’ children have this disease, so it’s incredibly hard to get funding. It’s incredibly hard to get funding for it,'” he continues. “That really stayed with me because I was like, oh, the weirdness of Craig’s kid having this, and Craig having access to this whole world of people who could possibly help. It just felt like the easiest call in the world to answer where you’re like, ‘Oh yeah, I can show up and help bring a spotlight onto this thing and this man’s research that saved Elliot’s life.'”

“It’s just this thing that feels personal to me in the best way, but it’s really just me like loving and supporting my friend, at the end of the day,” the Liberal Arts director adds.

To learn more about Dr. Paul Grossfeld’s research and how to support his efforts, head to the link here.