Almost five days into a judge-alone trial late last year, Cassidy pleaded guilty.
Cassidy was charged in 2019, after the child disclosed what had happened.
"Slowly it all started to make sense," the boy said as he read his victim statement.
The boy told the court he'd struggled severely, but was determined to succeed.
"You will no longer have an impact on my life. I've made it through something this tough and negative."
The boy told Judge Pippa Sinclair: "I want to prevent him from doing this to another child."
The boy's mother said Cassidy's abuse was a disastrous "tsunami" for the family.
She said Cassidy used Christianity to ingratiate himself but created a "hellish, poisoned" environment.
"He loved games and strategy and he played the long game with our family."
"His actions were cruel and calculating. There are no winners here."
The court heard some people didn't want to hear about the abuse.
"We've lost family and friends because of the social stigma of your heinous behaviour," the mother said.
"You took away his innocence. It will take more than one generation to recover."
Like her son, she ended defiantly, telling Cassidy: "I take my power back from you."
Father's disgust
The boy's father said: "I consider your actions to be satanic."
"I love my son as much as life itself, as the majority of parents do."
The father quoted Matthew, Chapter Seven, where the gospel warns readers about false prophets.
He told Judge Sinclair: "Give us the justice. Safeguard our children from predators such as Matthew Cassidy."
Defence counsel Guyon Foley accepted Cassidy committed an egregious breach of trust.
He said his client acknowledged the offending hurt the Cassidy family and the boy's family.
"Regrettably, the defendant clearly lost his moral compass."
But Foley challenged claims Cassidy was a "surreptitious predator", saying the betrayal could have been far worse, given many chances Cassidy had to offend.
Foley said the offending did not escalate over time, which was odd.
"It doesn't make sense if this is a terrible, incorrigible sexual predator."
The defence lawyer said Cassidy offered to make amends and posed a low risk of re-offending.
He said the healing process had started, but would take time.
"Do we need to rehabilitate this man? Yes we do."
Crown prosecutor Kirsten Lummis said it was incorrect to suggest Cassidy encouraged the boy to disclose the abuse.
"It's part of that warped set of beliefs that Mr Cassidy appears to have around the offending."
She said victim-blaming was a feature of the offending, and Cassidy benefited from not having to give evidence in his defence at the November 2020 trial.
The boy did not have that opportunity at the trial.
"His distress and sadness when giving evidence was palpable," Judge Sinclair said.
"You planned weekends away ... Booking accommodation on one occasion under a ruse that other people were going to be with you."
Judge Sinclair said Cassidy betrayed the boy's family who trusted him.
The objectionable material related to cartoon-type sexual content on Cassidy's phone featuring an adult male and underage girl.
Judge Sinclair said a psychiatrist reported Cassidy voiced remorse and was getting counselling and treatment.
"It appears you are receptive to continuing to address this."
He had much work to do, needing stability and intense rehabilitation, the judge added.
Cassidy was sentenced to 11 months' home detention and a further 12 months of post-detention conditions.
A decision on adding Cassidy to the Child Sex Offender Register will be made later.
Where to get help:
• If it's an emergency and you feel that you or someone else is at risk, call 111.
• Kidsline: 24/7 help for children and young people, run by trained youth volunteers: 0800 54 37 54
• If you've ever experienced sexual assault or abuse and need to talk to someone call the confidential crisis helpline Safe to Talk on: 0800 044 334 or text 4334 (available 24/7).
• Male Survivors Aotearoa, for confidential support nationwide. Also on 0800 044 334 or 4334 by text.
• Mosaic - Tiaki Tangata: 0800 94 22 94 (available 11am - 8pm).
• Alternatively. contact your local police station.
• If you have been abused, remember it's not your fault.
