Cameron Park's Phoebe Lee, 15, is going through a frightening ordeal, but she's trying to stay strong.
Mum Kelly Lee said Phoebe came home from school a fortnight ago and vomited.
"She had pain under her ribs and the bottoms of her eyes started turning yellow," Miss Lee said.
"We took her to John Hunter and her liver had started shutting down. Her whole body is jaundiced now."
Phoebe will need a stem cell transplant.
Her sister Makayla, 21, and brother Damon, 14, have been tested to become potential stem cell donors.
"We're waiting on results to see if they're eligible to do it," Miss Lee said.
Family friend Trudy Whitcombe has started a GoFundMe, titled "Funds for Phoebe's Life Saving Treatment".
Mrs Whitcombe described Phoebe as a girl with "a cheeky personality that brings joy to all around her".
She said the family "doesn't have a lot of money".
"They're having to pay for medications, along with general expenses," she said.
The Red Torquettes Women's Social Motorcycle Club and Women on Wheels are organising a "dice run" fundraiser for Phoebe in October.
Phoebe is suffering from a suspected case of aplastic anemia, a rare condition in which the bone marrow is unable to make enough blood cells.
She's still undergoing tests to confirm diagnosis of this blood disorder because she hasn't had the fever that normally comes with it.
Doctors did a biopsy and found "her bone marrow is disappearing at a rapid rate".
"They checked her bloods and she has zero white blood cells at the moment," Miss Lee said.
"Her red blood cells and plasma are dropping. They're getting dangerously low.
"They thought it was a virus at first, but they now think it's her immune system attacking itself."
Bone marrow stem cells can be damaged by this, while hepatitis and liver failure are associated with it.
"Her liver is stable now because they are giving her vitamin K shots, phosphate and other things so it doesn't fail," Miss Lee said.
Phoebe's eldest sister Brodie, 26, has had three liver transplants due to a condition called biliary atresia.
She's also had a kidney transplant, with mum Kelly the donor.
"I gave her a kidney on her 13th birthday," Miss Lee said.
"I was diagnosed with Lyme disease 10 years ago, so I've been very unwell for years too."
Phoebe's family hopes she won't need a liver transplant.
"It depends how much damage is done," Miss Lee said.
Phoebe said she was "coping the best I can".
"I understand why the treatments I'm having will help me get better," she said.
"I'm getting strength from knowing I have a chance to get better again, and having great support through this hard time."
Miss Lee said Phoebe had "watched her sister go through so much".
"She was brought up with her sister being ill. Brodie is such a trooper and so strong that Phoebe has learnt what to do to get better.
"So she's coping well under the circumstances. I'm very proud of her."
