Cairo Williams is facing an uncertain future after suffering a sudden and frightening decline in his mobility.
"One minute I was playing Lego and the next I was at the hospital," Cairo said.
The 10-year-old, of Marks Point, lost function on the right side of his body.
He described what happened to him as "all of a sudden, boom".
Through an MRI, doctors found a golf-ball sized cyst on his brainstem.
"It's like a ball of fluid," his mum said.
He was admitted to John Hunter Children's Hospital in May and is expected to remain there for another few weeks.
He went through an eight-hour surgery, but it was unsuccessful despite the best efforts of the surgeons.
"The surgical team cut a big hole in the cyst to drain the fluid," his mum said, adding that it refilled in the days after.
"The cyst is sitting in a precarious spot, so they're not able to remove it."
A GoFundMe has been established, titled Cairo's Fight for Recovery, to help with daily living costs while his mum and grandparents provide full-time care.
"This is a family who has always shown up for others. Today, we're asking our community to show up for them," Cairo's grandmother Shelley Williams said.
Cairo has full feeling in his right foot, but it "flops underneath him".
"When he's walking, it's like when your foot and hand goes to sleep," his mum said.
"He has a loss of motor control on that right side - the hand, leg and foot. He has stroke-like symptoms."
He's mostly in a wheelchair because of the high risk of falling.
Doctors don't know what caused the brain cyst.
"The neurosurgeons say it's a mystery. He could have had it at birth. It had an accelerated growth over the last three months," his mum said.
"We've met quite a few kids in John Hunter with a brain cyst needing surgery. Most of the time the surgery is successful because of where the cyst sits in the brain.
"Cairo's grew in his brainstem, which is a really high risk area."
He is having intensive rehabilitation with an allied health team at the hospital to try to regain some of his function.
"He has shown tremendous tenacity. He goes above and beyond and gives 100 per cent in the therapy sessions, but he's not seeing results yet. That's the hardest thing for his mental health and wellbeing," his mum said.
"We're not sure to what extent his recovery will be. Brain injury rehab can take a number of years.
"It's still not safe enough for him to go home without the necessary supports, which would be funded through the NDIS. We're not able to go home without all the right assistive equipment and supports to help him maintain a level of independence."
His mum will be heavily involved in his everyday care and support.
"That's the most challenging thing for him," she said.
"He was once climbing trees and riding bikes, swimming in the waves and running on the sand."
Cairo, who has a five-year-old brother named Nile, can no longer do his much-loved art.
"It's been completely stripped away from him. He can draw lifelike amazing pictures. At the moment, his right hand won't let him do that," his mum said.
"It's a big loss for him. We're needing to explore other ways of being creative."
