Ari Schultz, the 5-year-old Massachusetts boy who captivated the Internet in March with his sweet reaction to news he'd be receiving a heart transplant, has died

The 5-year-old Massachusetts boy who captivated the Internet in March with his sweet reaction to news he’d be receiving a heart transplant has died.

Ari Schultz earned the nickname “Danger” by his family for his brave attitude amid his long health battle — one that put him through more than 10 operations, including the aforementioned heart transplant.

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His family announced the news of his death on Facebook Friday — writing “Ari passed away peacefully this evening listening to the Red Sox.”

Genna Rosenberg, a friend of the Schultz family, tells PEOPLE that she will fondly remember Ari, who the “world fell in love with.”

“It’s heartbreaking,” she said. “Ari Schultz lived a remarkable life in his five short years, surrounded by family, friends and sports, which he loved more than anything. The Schultz family bravely and selflessly shared Ari’s harrowing story with the heart community and the world, to shine a light on children’s heart disease, the miracles of science, and the power of hope. They invited us along on Ari’s journey, and we got to know the pint-sized, but larger than life sports icon. The world fell in love with Ari. He seized each day with the most incredible enthusiasm, and a place for himself straight into the hearts of strangers who watched and rooted for Ari and his new heart.

“We join the world in mourning Ari, and surrounding their family during this heartbreaking journey,” she continued. “His legacy will surely live on.”

The sad news comes a day after Ari’s parents, Mike and Erica Schultz, revealed he had been admitted to Boston Children’s Hospital’s emergency department and placed on life support. “We called 911 at 4:19 a.m. as Ari was having a seizure,” they wrote on their Facebook page and Echo of Hope blog Thursday morning. “Very scary. At the hospital now. Something is going on. We don’t know what.”

Hours later, Ari’s situation got worse. “Just after 10 a.m. Ari coded in the emergency department,” another post read. “He had over a half an hour of CPR and has been placed on life support in the cardiac intensive care unit. Path forward unknown.”

Ari’s story first made headlines after a video shared on March 3 went viral of his parents telling him that he’d be receiving a heart transplant after spending 189 days at Boston Children’s Hospital and 2011 days on the transplant list. Wearing a Red Sox jersey and swinging around his baseball bat, Ari is enthusiastic in the clip — telling his parents “they found one!” and asking if he could go to a baseball field afterwards or practice his golf swing in the backyard.

The boy was diagnosed at his 18 week ultrasound with critical aortic stenosis and evolving hypoplastic left heart syndrome — and was the first person ever to undergo two successful heart surgeries before he was born.

Two weeks after Ari’s surgery, he experienced acute rejection to his new heart and on March 22, he went into cardiac arrest. Miraculously, he pulled through on April 15 and started to breath on his own. He was released from the hospital again on June 16.

During his time at home, Ari remained on Oxygen and spent time with family including siblings Lexi, 3, and El, 10 months — according to posts on his family blog. There were also a number of high-profile visitors, including Red Sox catcher Christian Vasquez and shortstop Xander Bogaerts — who invited him to throw out the first pitch at a Red Sox game on Aug. 27

In June, Ari also met golf legend Hale Irwin at the U.S. Senior Open.

On April 18, Mike and Erica started a campaign to try and save 100,000 lives after learning from their own experience that there are not enough organ donors.