Boyce's sister Maya took to Instagram days following the tragic news to share a heartbreaking letter alongside a slideshow of childhood pictures.
"Yes, he died," Maya wrote/ "Yes, I'm sad. Cameron was my best friend. He is someone I will always idolize. His smile could light up a room, unlike anyone else's. He was perfect. He always said that if you have a voice, you have the privilege of using that voice for change, and he did not take that idea lightly. He understands his responsibility as someone so many kids would look up to."
"Cameron always went out of his way to be giving and kind," Maya continued. "He did more with his 20 years of life, than most people ever could with 100 years. He was actively charitable. He travelled the world. He made creativity and art his life's mission and he encouraged others to do the same. Of course, I am devastated. I will be for the rest of my life. But what I'm holding onto, and what I encourage you to hold onto as well, is the memory of his endless optimism. He was sunlight wearing shoes. I can confidently say, he wants us to celebrate, grow, and persevere."
She added, "Yes, he died. Yes, I'm sad. I'm also happy. And grateful. I was with him hours before he died. It was normal and fun. We said, 'I love you.' He was happy. I spent 17 years knowing what it was like to be loved by Cameron Boyce. That is the most beautiful gift I have ever received."
A spokesperson for his family told ABC News: "It is with a profoundly heavy heart that we report that this morning we lost Cameron. He passed away in his sleep due to a seizure which was a result of an ongoing medical condition for which he was being treated.
"The world is now undoubtedly without one of its brightest lights, but his spirit will live on through the kindness and compassion of all who knew and loved him," the statement continued. "We are utterly heartbroken and ask for privacy during this immensely difficult time as we grieve the loss of our precious son and brother."
“Too young. Too sweet. Too funny. Just the nicest, most talented, and most decent kid around. Loved that kid,” Sandler wrote on Instagram of Boyce, who played his son Keithie in Grown Ups and Grown Ups 2. “Cared so much about his family. Cared so much about the world. Thank you, Cameron, for all you gave to us. So much more was on the way. All our hearts are broken. Thinking of your amazing family and sending our deepest condolences,” Sandler added.
Actress Peyton List, who played Boyce’s sibling on Jessie, mourned his death in a heartbreaking Instagram post. “He was younger than me but taught me how to spread love and kindness more than anyone that has ever been in my life,” she wrote. "There is a hole in my heart that will never heal left for you. I will never stop talking about you."
Actress Selma Hayek said, "I had the privilege to play Cameron’s mother in #grownups 1 and 2 and we stayed in touch through the years He was spirited, talented, kind, generous, funny and a shining light. His joy will live in our hearts forever as he goes on dancing and shining elsewhere. My heart goes to his lovely family."
In a statement released to ABC News, a Disney Channel spokesperson said: "From a young age, Cameron Boyce dreamed of sharing his extraordinary artistic talents with the world. As a young man, he was fueled by a strong desire to make a difference in peoples' lives through his humanitarian work.
"He was an incredibly talented performer, a remarkably caring and thoughtful person and, above all else, he was a loving and dedicated son, brother, grandson and friend. We offer our deepest condolences to his family, castmates and colleagues and join his many millions of fans in grieving his untimely passing. He will be dearly missed."
Kenny Ortega, director of The Descendants, The Descendants 2 and The Descendants 3, shared a behind-the-scenes photo from set alongside an emotional tribute.
"My Love, Light and Prayers go out to Cameron and his Family," Ortega wrote. "Cameron brought Love, Laughter and Compassion with him every day I was in his presence. His talent, immeasurable. His kindness and generosity, overflowing. It has been an indescribable honour and pleasure to know and work with him. I will see you again in all things loving and beautiful my friend. I will search the stars for your light. Rest In Peace Cam. You will always be My Forever Boy!"
Boyce was honoured in April with the Pioneering Spirit Award at the 9th Annual Thirst Gala. He has raised more than $30,000 for the Thirst Project, which raises awareness about the global water crisis, to help build two wells in Swaziland.
“Many people have the heart to give back, but a lot don’t know how to. I try to be the bridge for those people – whether that means getting them involved in one of my campaigns or inspiring them by showing them a blueprint of how to get others engaged,” he said prior to his death.
Gregg Sulkin wrote a heartbreaking tweet, "Heartbroken. Lost for words. I had known Cameron Boyce for many years. He was always polite. Always respectful and always a class act. In fact I was going to message him a couple weeks ago to tell him that I wanted to be in each other’s lives more."
Skaii Jackson said, “I don’t even know where to start… I am at a loss for words. I never thought in a million years I would be writing this,” she captioned the post. “Cam, you were one of a kind. My heart will be forever broken. I am so happy that I got to spend almost every day with you on set, you gave the best hugs… Thank you so much for being the big brother I never had… I am so distraught and I cannot stop crying!”