Each of the victims were female, left in his sole care and vulnerable to the sexual abuse; two of them with significant physical and mental impairments.
The jury heard from one complainant with a severe intellectual impairment, who recalled feeling "scared" when the offending began.
She said she never told anybody what was happening because she thought she would get into trouble and the jury later learned she had an IQ level significantly below the population average.
A clinical psychologist testified to the complainant's understanding of power differentials, being that the person with less power in a relationship would be the one to get into trouble.
Another complainant testified she saw the man sexually abusing another female with impairments so severe she was unable to talk.
She remembered one incident when she was trying to change the female into her pyjamas when the defendant entered the room and insisted on changing her himself.
"I heard her making her noises . . . so I went down [the hallway] and he was on top of her,"
It took the jury just under six hours to find the man guilty of all of the charges, which were amended throughout the trial to reflect the evidence given.
Gasps were heard from the public gallery as, one by one, each of the guilty verdicts were read out, for a total of 15 sex charges.
The jury found him guilty of five charges of sexually exploiting a young person, five of rape, two of sexual conduct with a child under 12 years old and one each of attempted rape, indecent assault and unlawful sexual connection.
Defence lawyer Scott Jefferson called a handful of witnesses known to the defendant who each testified they had never seen anything untoward about his behaviour towards those in his care.
The court heard the children entrusted in the man's care had very good lives, with birthday parties one had to see to believe, and that he cared for them like they were his own.
However Ms Rielly said each of these defence witness' testimonies, while well-meaning, seemed "contrived" and asked that the jury consider the fact the alleged abuse happened in private when no-one else was around.
"It's clear that all of the defence witness love the defendant, care about him and respect him. It's also clear he has done a lot of good for his family and community over the years . . . but what I'd say to you is many otherwise good people do bad things."
In her summing up, Judge Bridget Mackintosh told the jury it was only human to feel sorry for people who are disabled and have those challenges in their lives, and they could feel equally sorry for people accused in cases like these.
However, there was no room for that in this case and they had to put aside any feelings of sympathy and prejudice, she said.
The man's face was expressionless as the verdicts were read out, however he leaned over and spoke to the jury as he was taken from the dock.
He was remanded in custody to appear again later this month for sentencing.
