Ronnie, an 11-year-old boy, was diagnosed with a rare and aggressive brain tumor called a diffuse midline glioma.
After undergoing chemotherapy and radiotherapy, his tumor shrank, but not enough to meet the criteria for an experimental drug called ONC201, which is available on the NHS.
The drug requires the tumor to be a certain size, and Ronnie's tumor is just a millimetre too small.
His family is now fundraising to afford the drug privately, which costs a significant amount of money per month.
