Indi fell onto synthetic turf on February 27, 2024, and later presented to Warrnambool Base Hospital where her stepdad Damien Simpson said they were sent home with "nothing to worry about".

But the family, including mum Stacey and 20-month-old son Harley, soon returned to the emergency department as Indi's condition worsened.

She could no longer walk which was unusual for a young girl who loved being outside, riding her bike and playing soccer.

Indi spent a week-and-a-half in Warrnambool Base Hospital where Mr Simpson said she was misdiagnosed with Functional Neurological Disorder (FND).

He said she was then discharged, despite having high blood pressure and being unable to walk, go to the toilet or feed herself.

Once home the Simpsons provided Indi with round-the-clock care, which was difficult for Mr Simpson who suffered a broken neck in a workplace incident in 2019 and his wife who has erb's palsy (a paralysis of the arm) and tennis elbow.

"We knew she was really, really sick and we were doing everything we could to get the help we needed but we felt like it was falling on deaf ears," Mr Simpson said.

"I had researched FND and it didn't come with blood pressure that was 133 over 111 which it has been recently."

Mr Simpson said they brought Indi back to the emergency department three days later and she was re-admitted.

He said the next fortnight was filled with counselling and physiotherapy appointments but his little girl appeared to be getting progressively worse.

Mr Simpson said after being denied a specialist referral he sought a second opinion.

A private GP then made an urgent referral to the Royal Children's Hospital.

On March 29 Indi was formally diagnosed with Guillain Barre Syndrome, a rare disorder caused by the body's immune system creating antibodies that attack the nerves.

She requires a wheelchair, suffers severe fatigue, pain and numbness in all limbs and has difficulty swallowing.

Indi is expected to remain at the RCH with her mother for months while Mr Simpson stays in the nearby Ronald McDonald House.

Their son Harley remains in Warrnambool with Stacey's parents.

"We miss him like crazy but we obviously have to be here for Indi," Mr Simpson said.

"It has been so hard."

Mr Simpson said while he was hopeful for Indi's recovery there was still a long road ahead of them.

"Indi is frustrated and it is extremely distressing for her going from being able-bodied to virtually paralysed from the waist down," he said.

"It's rather hard for her to grasp the concept of what is actually happening to her. As a parent it's heart-breaking, you literally leave the room in tears.

"We're fairly positive but also very stressed that it could be a 12-month turnaround before she can come home."

Mr Simpson said Indi was being treated with intravenous immunoglobulin - a pooled antibody used to manage various immunodeficiency states, and pain relief and antibiotics for a urinary tract infection that was left untreated for up to six weeks.

"That is what the distressing part is, knowing it could have been left undiagnosed for such a long time," he said.

"It could have been life-threatening. We could have lost her."

A South West Healthcare spokesperson said SWH was "sorry to hear of this diagnosis and understand it is a difficult time for the family"

"We're in the process of reaching out to the family directly to seek further information and to discuss their experience of the care provided at South West Healthcare."

It declined to answer questions about Indi's care and diagnosis.

A family friend has set up an online fundraiser for the Simpsons to help cover the costs of travel, medical costs and other expenses.