Boyce died at 20 in July 2019 after suffering a seizure in his sleep due to epilepsy.
"I think that Cam was the most alive person I've ever known," Cameron told PEOPLE exclusively. "I think that in that, he has inspired me to be more alive, he has inspired me to be more human, more deeply feeling."
"And I think that's one of his legacies, he touched people in that way," she continued. "In a way that I don't know anybody else has. And also of course, wielding peace for all of the world."
The Disney Channel star called the loss of Boyce "eternal" and added "the pain is lifelong."
"It just changes and shifts position in your nervous system, but I don't think it ever goes away," she explained of her grief. "I don't think you find peace, but I do think grief finds a way to transform you for the better, make more space in you to hold more of it.
"You become bigger," she added. "It's not that the grief becomes smaller, you just become bigger to accommodate."
Cameron also said it was "highly emotional" to attend the event, which was organized in support of the Cameron Boyce Foundation's mission of curing epilepsy through funding research, education and awareness.
"I think that we all were so intimately close with Cam and a lot of us haven't been all together since his celebration of life," she shared. "So it's definitely a lot of mixed emotions but I know a lot of us are very excited about carrying on the work he wanted to do and couldn't finish so we're very excited about that."
Carson, who performed at the event, also called the evening "surreal and emotional."
"Cam always said that we all go, but what we leave behind should be bigger than us. That's exactly what he did," she told PEOPLE. "Feeling Cam's presence and loving him and being loved by him was like feeling sunshine."
In an emotional Instagram post, the Feel the Beat actress reflected on her lasting relationship with Boyce's family, including his parents, Libby and Victor, and sister Maya.
"Our hearts are forever yours," Carson wrote in the moving caption.
On the red carpet, Victor acknowledged it was "nerve-wracking" putting together the fundraiser, and Libby told PEOPLE the "bittersweet night" ultimately was a way for them to honor their son.
"We have decided that this will not be a sad event," said Libby. "Moving the needle on epilepsy is just so critical to us, but it's in this environment of joy."
Cameron's sister Maya attended the event with close friends and said "the familiar faces have been very comforting" after losing her brother.
"Of course I'm feeling sad, but I'm also happy for my parents," said Maya. "This has meant so much to them. My mom started the foundation a little less than three years ago, and this is exactly [Cameron's] style — outdoors, intimate, with everyone he knows. It feels exactly like Cameron."
Other loved ones in attendance included Boyce's former Descendants costars Sarah Jefferey and Maz Jobrani.
"I think of him daily. I play the music that he showed me," Jefferey told PEOPLE of how she keeps Boyce's memory alive. "Keeping in touch with the people who also knew him is huge. We're all rallying and supporting each other, and I know he feels the love."