He went into remission for years, but in 2017, Miguel’s cancer returned. That’s when, Mrs. Cedeño said, everything changed. It was a race against time to get him proper treatment.

“I had to buy everything,” she said. “The chemotherapy, the antibiotics, the needles. But now it’s even worse. I have to buy gloves, cotton, alcohol, water, even the tubes for the lab if I need to ask for a blood test.”

Venezuela’s main hospital has become a symbol of the catastrophic unraveling of the country’s health care system. It is often without running water, medicine and even doctors. The electricity regularly cuts out, which has resulted in patient deaths, opposition politicians say.

Mrs. Cedeño said she has never been a fan of the protests, but her son has told her he is eager to attend them.

“He said, ‘Mom, I want to go out and make them feel the rage I feel everyday I am at this hospital without any help,’” she said.

“I have faith and hope.”

Sunny Balza, 35

Mr. Balza, 35, was a captain in the Venezuelan National Guard and quickly moved up the ranks, gaining the trust of officials who grew to rely on him, including Nicolás Maduro Guerra, President Maduro’s son. But he didn’t always support the decisions of his superiors.

“I never agreed with their lines, ever,” he said.

Two years ago, he fled Venezuela for the United States, where he now manages a company. Mr. Guaidó, as interim president, has proposed amnesty for members of the armed forces who are willing to break with Mr. Maduro’s government, but Mr. Barza is unsure whether he will return.