(CNN) The efforts of some hardworking preschoolers are warming people's hearts, and it's not just because of all the hot cocoa.

Jasper Mazzocco, 4, was diagnosed with a rare type of brain cancer late last year. He was taken out of school and hospitalized, but his classmates at Redding Cooperative Preschool in Redding, California, never stopped thinking about him.

"The kiddos... miss and talk about him everyday," Becky Haskins, a fundraiser organizer and mother to one of the preschoolers, told CNN. "He is one of the sweetest souls that I have ever met and his family is just the same."

Jasper Mazzocco, 4, smiles from his hospital bed.

Last week they held a hot cocoa fundraiser, hoping to raise money for Jasper's family. With help from their parents, local stores and the community, the stand was a massive success: altogether they raised more than $10,000.

"They wanted to help Jasper in any way they could," Haskins said. "That was a day that I will never forget."

A community effort

Haskins said her daughter suggested they sell lemonade to raise money for Jasper, but with the wintry weather she steered the brainstorm towards hot cocoa.

The local Trader Joe's provided space and supplied water bottles, a Dick's Sporting Goods offered to set up tables and chairs, and both the Costco and Starbucks donated baked goods.

Three Starbucks employees even made back and forth runs to supply hot water to make the cocoa.

Jasper's preschool teacher, Jessica Stephens, said some of the people who stopped by the sale were cancer survivors themselves, and many shared stories of their own battles with cancer, or the ones they lost along the way.

"So many tears were shed in those six hours," Stephens told CNN. "This experience has been the most beautiful thing I have ever been a part of."

Recovering from surgery

Jasper's mom, Shelby, told CNN that the 4-year-old had surgery on Monday, and if everything goes well he will start treatment again next week. In the meantime, his friends are checking in. They held a phone call earlier this week.

"It's was really neat to know they miss us as much as we miss them," Shelby told CNN. "He was on the phone with them [on Monday] saying 'Hi' to everyone and singing his little preschool songs with them."

Jasper Mazzocco smiles from the hospital bed.

Jasper can't see at the moment, but Shelby says her toddler is listening to her reading all the cards his friends sent, and listening to the audio from the videos, too. In an update to supporters, she added he's showing more interest in his toys and is telling more and more jokes every day.

In addition to the hot cocoa stand, more than 350 donors have raised over $30,000 on GoFundMe for Jasper's family.