Liu Weixiong, who used to care for children with mental issues in Malaysia and Singapore, is keen for people of all ages and from all walks of life to join the program, because the classroom is about companionship as much as study.

"We welcome seniors, who can share their stories and experience. They are needed to help the children grow."

So far, the Beijing New Sunshine Charity Foundation has opened 26 ward classes in and around hospitals in 13 provinces. More than 5,000 children have attended them. However, the classes only have 17 full-time or part-time teachers, such as Liu Weixiong.

The students aren't all leukemia patients, though, as some have other forms of cancer, and kidney diseases. All require long-term treatment.

Liu Zhengchen plans to expand the faculty and provide more courses for children of different ages.

"I hope we can help more children with serious illnesses to maintain their studies and social adaptability so they can return to living normal lives as soon as possible," he said.