Her devastated dad Russell Milne has recounted to ABC's 7.30, how it was discovered that Yoey faced a fight for her life.
Russell was working away on a farm in rural Queensland when he received the news that the Royal Brisbane Hospital had diagnosed Yoey with a genetic mitochondrial disease and she didn't have long to live.
Not wanting to give up on his girl, Russell arranged for her to be flown to Sydney where a shocking discovery was made.
Doctors told Russell that Yoey didn't have a genetic disease at all, instead her mum had Munchausen syndrome by proxy.
The psychological condition is when a care-giver, often a mother, craves attention so they either make up or create an illness make it look like a child is sick.
After the diagnosis in 1984, Yoey was taken away from her mum and started to gain weight.
Although Russell had been working away and didn't know what had been happening, he also lost custody of Yoey and she was put into the care system.
Russell gave up his job and dedicated his time to navigating the court system to prove he was a capable father.
'I remember in those days I would write everything on a typewriter and if you got one letter or word wrong, they'd send it back to you and you'd have to do it all over again,' he told ABC's 7.30.
By then, Yoey was showing signs of autism and had epilepsy and delays due to her mistreatment.
Not regaining custody, for the next 20 years Russell only saw Yoey once in 1991. Instead, she was moved through foster homes and group homes and suffered sexual abuse.
By now Russell was an art teacher and had started another family. He continued to write letter to find out how Yoey was and eventually thought she was dead.
'We kept sending stuff but we never got any reply,' he told 7.30.
When Yoey was 22 they were finally reunited. Yoey is now in a group home and has cataracts caused by self-harming, anxiety and autism.
In 2002 she was also diagnosed with the developmental disorder Smith-Magenis syndrome. The diagnosis left Mr Milne wondering if this could explain why his girl was starving when she was young and whether she'd been put into care for the wrong reasons. Although he still suspected the original Munchausen by proxy diagnosis was probably also accurate.
Russell is planning to share Yoey's story at the Royal Commission into Violence, Abuse, Neglect and Exploitation of People with a Disability.
'She’s lived a life of hell.' But despite it all, he says, 'she’s an amazing human being'.