A Brisbane mum wanted to explain her cancer to her son. So she wrote him a book.

“The doctors have told my mummy that her cancer will never go away. They just have to keep it asleep with lots of medicine.”

It can be easy to forget that the things we take for granted are more difficult for children to understand.

Brisbane mum, Donna Penny,  42, was first diagnosed with breast cancer seven years ago. Since then, she has been battling the disease as it has spread to her lymph nodes, shoulder and spine.

My gorgeous little man came to chemo. Dying is not an option. #mylittleman #dyingtoyoung #neverstop #live #life #myson

A photo posted by Fighting to live ???? (@love.donna.penny) on

With her condition comes hair loss, weakness and a great deal of time in hospital. Donna spent a long time grappling with how to explain what was happening to her to her son, Kai, who has never known a time when his mum was well. She was first diagnosed with cancer when he was just one year old.

Donna searched for a book that would explain her illness to Kai, but was disappointed with what was available. “They were just morbid, and sad, and I didn’t even read them to him,” she told The Daily Mail. “I showed my husband and I said I’m not showing this to our child.”

Donna has written her own heart-felt children’s book, from the perspective of a child whose mum is battling cancer. This beautiful video shows nine-year-old Kai reading a section of the book, which Donna hopes will be a help to other families fighting the disease.

“I wanted to write a children’s book that was beautiful and bright, and not something a parent would be afraid to read to their child if they had cancer,” she said.

For more information on Why My Mummy? and to follow Donna’s journey, visit her Facebook page or follow her on Instagram. You can also donate to her crowd funding campaign here.