Rumer Maujean is fighting stage 4 neuroblastoma. Photo: gofundme/jezanw

It's a family battle which has no winners and, tragically, at the centre is very sick little girl who is fighting for her life.

The plight of two-year-old Rumer Rose Maujean came to light this week after her father was charged by police for giving his daughter cannabis oil to treat her cancer.

Adam Koessler was arrested at Lady Cliento Children's Hospital, Brisbane, last Friday, and was charged with supplying drugs to a minor under 16 years of age. He is banned from having any contact with his daughter as part of his bail conditions.

Adam Koessler, who has been charged with supplying drugs to a minor, with his daughter Rumer. Photo: Facebook/AdamFearlessFather

Rumer was diagnosed with aggressive stage 4 neuroblastoma on Christmas Eve last year.

The little girl, whose parents are estranged, relocated with her mother from Cairns to Brisbane in order to have surgery on an 11cm adrenal gland tumour which was wrapped around her spinal cord.

Doctors have told Rumer's family she has a 50 per cent chance of survival.

Mr Koessler claims his daughter showed a "miraculous" improvement in her condition after he gave her the cannabis oil.

"Her cancer ridden little body was ALIVE AGAIN - Rumer had almost instant quality of life," Mr Koessler wrote on his Facebook page Fearless Father.

"She would say 'Daddy, tummy's NOT SORE'. She would be able to eat like a champion and began to gain weight, her energy was up and (she) wanted to go outside with me instead of lay on her back with legs curled up.


"Her skin colour came back, her eyes were sparkling again. Rumer's delightful behaviour was restored."

Despite Mr Koessler's statements about the positive effect of the cannabis oil, Rumer's mother Sacha Maujean says much of what her ex-partner claims is "very false".

The single mum of Rumer and ten-year-old daughter Romany agrees with the police decision to charge Mr Koessler over the cannabis oil.

"It is true he has been arrested for supplying a dangerous drug to a minor and I support the Child Protection Unit's decision to arrest him and charge him," Ms Maujean wrote on her GoFundMe page, which was created to raise funds for the family.

Since being arrested and charged Mr Koessler has taken to social media to campaign for the rights of parents to administer medical grade cannabis oil to relieve suffering for their sick children. He also has a competing fundraising site.

His Facebook page has already attracted more than 16,000 followers who are also keen to see medical marijuana legalised in Australia and around the world.

"To update everyone. We are in the process of organising a petition, an email campaign and protest in Brisbane and other cities," a post on Mr Koessler's page reads.

Meanwhile, Ms Maujean continues to update people on her daughter's progress on her Facebook page Rumer's Recovery, and has asked people to focus only on her daughter's fight against cancer, not the family issues which may be occuring.

Rumer has had surgery and is currently undergoing intensive, high-level chemotherapy treatment which is expected to run for 8 months.

The two-year-old had a setback earlier this week when she was admitted to intensive care after fluid built up in one of her lungs. Fortunately the stay was short, with the toddler soon getting back to her "bossy" self.

"Rumer came out of ICU yesterday and is much better! She is sitting up and bossing everybody around again, huge improvement! We are on the right road to recovery," her mum posted on Tuesday.

Ms Maujean shared more good news Thursday morning: "A very hungry little girl woke up this morning wanting very specifically - sausages, bacon and mash potato - for breakfast! Nothing wrong with her appetite."

Mr Koessler is due to appear in Brisbane Magistrate's Court to face the charge on January 20.