William Tyrrell's biological father has been sentenced to seven months in prison over drug and theft charges.
Magistrate Kathy Crittenden acknowledged that Brendan Collins had suffered under the weight of his son's 2014 abduction and set an earliest release date for March 14.
Collins, who is also known as Brendan Clifford, was convicted of eight charges of having stolen items in his possession including bank cards, toys, novelty items and clothing.
He was also convicted of minor drug possession after police found him with a "minuscule" amount of methamphetamine, or ice and a glass pipe, reports News.com.au.
Bankstown Court heard on Friday that Mr Clifford had suffered from "flashbacks and psychological and emotional problems" since his then three-year-old son William vanished on September 12, 2014.
News.com.au revealed exclusively how Collins' life has unravelled since that say, with his descent into drugs, crime and mental problems
Brendan Collins laid bare harrowing details of his life since his missing son became the subject of Australia's biggest manhunt.
Collins looked strikingly like his son at his first public court appearance late last month since William became a household name.
Clean shaven, his brown hair shiny and his face looking fresh and surprisingly young for his 35 years, Collins shifted in his seat in a video booth in Silverwater prison on January 25.
One eye displayed a twitch as he leaned forward into the camera as he appeared via audio visual link in Bankstown court.
Arrested on January 15 and placed in custody on drug and theft charges, Collins swivelled on his seat as the court heard he had entered guilty pleas.
His hands thrust deep into the trouser pockets of his prison issue tracksuit pants, he listened intently as the magistrate and court appointed lawyer discussed his tragic past, and the fact he had been homeless and unemployed.
He was initially taken to Surry Hills police cells, where his mother Natalie Collins told news.com.au he sounded more cohesive than before his arrest.
She said Collins had spent several months in Parklea prison on drug charges last year, but since his released he had become a dishevelled disoriented mess.
He had hoarded rubbish and children's toys and "raged in his room" about protecting his children.
The charges for which he was appearing in court on Wednesday involved theft of toys and novelty items, and he was arrested while staying at a location where he was easily detected, and while wearing stolen clothes on a train with the security tags still visibly attached.
On Wednesday, despite looking nervous and exhaling loudly and gritting his teeth, he was extremely polite to the magistrate, telling her, "I'd like to get it dealt with now if that's fine please."
He even thanked her when she told him he would be spending more time in prison because his recent offending had "crossed the threshold" for being let off with a bond or a community based sentence.
This means Collins will be sentenced in the same week as Karlie Tyrrell, William's mother who is facing court over a charge of spitting at a police officer.
In between periods of homelessness, Collins has stayed in the spare room of the home occupied by Karlie and the former couple's two children, who are the younger siblings of William.
Collins looked thin and sometimes spaced out, with his eyes wide open. At one point he bent down to remove his jail issue shoes.
He confirmed to the magistrate that he could hear her and thanked her and then as his lawyer revealed his past to the court, he sat bolt upright in the prison video booth and gave the court his full attention.
"[Collins] has been homeless on and off for the last three years. Three years ago his life went through a terrible period," his lawyer told the court.
"He is the father of William Tyrrell who is missing and has been suffering a degree of trauma.
"Being homeless has spiralled his illicit drug use and he has seen a psychiatrist at Parramatta when he can afford it and has made some progress."
Court documents obtained by news.com.au reveal that Collins has been arrested three times in the last three months, during the period that his mother Natalie had said he resembled an old derelict, and she didn't recognise him.
The documents described Collins as homeless, unemployed and previously convicted of drug offences, breach of bail, warrants offences, violence against another person by stealing, and goods in custody.
On January 15 this year, police facts say, Collins went to the Great Southern Comfort Hotel in George Street, in Sydney's CBD.
The hotel's head chef had arrived for his shift at 11am and placed his Samsung S5 mobile phone on a bench while he went into the cool room.
When he came out the phone was missing, and CCTV would show Collins entering the closed restaurant, looking around and taking the phone.
The restaurant manager found him playing with it in a bathroom and questioned Collins who said he didn't own a phone and handed it over.
Police arrived and searched Collins and found on him an Asian religious figurine, a Star Wars toy and a Sydney souvenir magnet which they believed were stolen.
Court documents show that a month earlier, on December 18, Collins was spotted by police travelling on a westbound train near Blacktown wearing a pair of black Le Coq brand tracksuit pants and a white Cahill brand jacket, both with the security tags attached.
He told police he had the receipts, then said, "That's how my mum gave them to me."
In his pockets, police found five packets of Telfast hayfever tablets, two Energizer magnetic torches, Kodak photographic paper and a pen and notepad set.
In his wallet, they found a vial of liquid and a green plastic tube containing liquid.
The court heard Collins had been charged with possessing a prohibited drug.
On November 17, Collins was charged with unlawfully obtaining goods after police observed him walking "side to side" down a street in South Granville and kicking "a brick wall for no reason".
Police found him carrying an ANZ bank card, an EFTPOS card and a NSW Police Force civilian warrant card in the names of three men. He was also carrying bags including a clear plastic bag containing two $100 notes and three $50 notes.
On January 18, he was convicted in his absence after failing to appear in Parramatta court on having goods in custody, and unlawfully obtain goods charges.
"I was in custody your honour, OK thank you," he told Magistrate Kathy Crittenden when she asked why he had failed to appear on the goods in custody charges last week.
The court was told he accepted the charges, and that he would be receiving a custodial sentence.
"He has approached an employer while in custody and on release will have work as an excavator," Collins' lawyer said told Magistrate Crittenden.
"He has reconnected with his mother and grandmother and will be going to live with them and only if he's off all illicit substances.
"He tells me he plans to work, use the money to go back to the psychiatrist and stay off illicit substances."
She said Collins understood that he had "crossed the threshold" of hoping for a non-custodial sentence and accepted he would be remaining in jail after he was sentenced next week.
Ms Crittenden said that Collins had spent time in prison and had committed offences prior to his son William's abduction, including a common assault in 2010.
"I have come to view bearing in mind the offences for which Mr Collins is to be sentenced and his criminal history [and] he has served a week in custody that I would like to consider properly his sentence, so I will adjourn this matter," she said.
Collins leaned forward in the prison booth and said, "I understand that your honour. OK your honour, that's fair thanks."
When the magistrate added, "A term of imprisonment is warranted," Collins stood up and replied, "Right then, thanks your honour," and bowed deeply from his waist and disappeared back into Silverwater prison.
Natalie Collins told news.com.au that her son had been promised, on his eventual release, rehabilitation help from campaigners involved in raising awareness to find her grandson William.
"He needs counselling. He has stuffed up, but try being in the shoes on Brendan's feet," she said. "He has been suffering. I think police should arrest all drug offenders and sellers.
"But every day I think of William and Brendan just holds it in and doesn't talk about it."