Nick Cannon has opened up about the months between learning that his son Zen had cancer and his death.

In an episode of The Checkup with Dr. David Agus, the Masked Singer host, 42, opened up about how they discovered their young son had brain cancer.

Cannon’s baby boy was “healthy, lively, and usually smiling” at first, but around two months old, he began to notice the baby’s “strange” breathing patterns.

“My greatest regret as a father of many children is that I don’t get to spend enough time with them, partly because I work nonstop and partly because I’m overburdened.”

“He had a slightly larger head than the others, but my children all have enormous heads. I was born with a big head,” Cannon joked.

Zen’s parents took him to the doctor because they suspected he had asthma. The doctor immediately became concerned because the baby’s growth was the “first indication anything was happening.”

“They ran a slew of tests.” He remembered not being allowed to leave the hospital. “You may therefore assume that you are bringing your child in for a checkup to rule out the worst-case scenario, which is asthma, you know? It was also a surprise to learn that he has brain cancer.”

Doctors “sort of laid it out for me,” he said, asking them to “be straight” with him so he could prepare himself and protect Scott from whatever came next.

Zen was diagnosed with high-grade glioma, a rare and aggressive brain cancer. Chemotherapy was suggested as a treatment option for Cannon and Scott.

“When we first went to the hospital, just to decrease his head from fast continuing to grow, there were a handful of operations we were all for,” he said, describing how they used a shunt to drain fluid from Zen’s brain.

“That made sense to me. He felt less pain, and the surgery was completed quickly. It was all about living well,” he noted.

“From that point on, they informed me that your boy might survive to be 3 or 4 years old in the best-case scenario. When I first heard that, the first thing that came to mind was quality of life. I wanted him to have the best life possible.”

Cannon questioned whether chemo would prolong Zen’s life or lessen his suffering; they said, “Not really,” citing the tumor’s location.

“I couldn’t imagine your child having chemotherapy after seeing him hooked up to all of that equipment — and the fact that he had to have a shunt two or three times was heartbreaking each time.”

Cannon underwent chemotherapy as part of his lupus treatment and “understood what it did to me.”

“As an adult, I understood how that procedure worked. My hair was thinning,” he explained. “It drained you of everything; I wouldn’t even call it agony. I couldn’t even imagine what it would do to a newborn.”

The treatment option required Zen to “live in the hospital” and raised concerns about his quality of life.

Cannon and Scott eventually “got to the space of ‘we want to enjoy him, and we want him to enjoy u,’” he said, adding that “he would never have gone home.”

The final days were “difficult,” according to Scott’s father, who praised her “strength and tenacity.”

“I would not have succeeded without her. She handled everything because she was the only one. He nodded his head. We had some wonderful times.”

“We had the opportunity because we were aware of the upcoming change. Even on the final weekend, I knew it could be the last; it happened much faster than we expected.”

“Fortunately, we took in the sunrise, visited the beach, watched the sunset, said some lovely prayers as a family, and generally got closer as a unit in a very lovely way,” Cannon continued.

“I appreciate it, but it was extremely difficult. It was heartbreaking to see your child suffer and things stop working.”

In addition to Zen and their unborn second child, Cannon has a daughter, Powerful Queen, 23 months, a son, Rise Messiah, 10 weeks, and a second child, Golden Sagon, 5, with model Brittany Bell.

He has a 3-week-old daughter named Beautiful Zeppelin, 17-month-old twins named Zion and Zillion, and 11-year-old twins named Monroe and Moroccan with Abby De La Rosa. He also has a 5-month-old son named Legendary Love with model Bre Tiesi and a daughter named Onyx Ice Cole with former Price Is Right model LaNisha Cole, who was born in September.