Nick Cannon is opening up about fond memories he has of his late son, Zen.

"We had a short time with a true angel," the actor told People in this week's cover story. "My heart is shattered. I wish I could have done more, spent more time with him, taken more pictures. I wish I could have hugged him longer."

Zen died on Dec. 5 from a brain tumor, four months after he was diagnosed.

Cannon and Zen's mother, Alyssa Scott, worked to make every day special with their son.

"We focused on Disneyland, our favorite place," explained the 41-year-old entertainer. "Every month we would celebrate his birthday, just really seeing it as a victory every time he had a milestone that he was still here with us."

Cannon said Zen's illness became more serious over the Thanksgiving weekend, when he had trouble breathing.

"He was gasping for air. We'd wake up, and he wouldn't be breathing for maybe five to 10 seconds at a time, and then he'd let out a huge gasp," the TV talk show host recalled. "You could see it frightened him. It was the scariest thing I've ever experienced."

Anticipating that Zen was dying, Cannon and Scott made the decision to spend the day with their son at the beach.

"I was like, 'We have to watch the sun rise and just be here with him one last time,'" he told People. "It was beautiful."

"He was the most loving baby," Cannon said. "I look at being his father as a great privilege."