But the response by a Catholic school has highlighted what still needs to change to protect children, Mr Boock believes.
Mr Boock (64), the brother of former New Zealand cricketer Stephen Boock and sports journalist Richard Boock, has confirmed he was sexually abused for nearly a year at his Dunedin home in 1967-68.
And his abuser, a 19-year-old student named Robin Pettit, was later allowed to continue teaching at St Bede's College, a Catholic school in Christchurch, even after his past offending was revealed.
Mr Pettit admitted his offending when contacted in Christchurch last week, telling ODT Insight he "had a bad period there'' after finding out he was adopted.
"Yes, it was a very serious thing that I did. I'm very regretful about it all, but I can't go backwards.''
Mr Pettit also confessed directly to college rector Justin Boyle when Mr Boock complained in 2011, but he was allowed to continue teaching, with no extra precautions, until retiring in 2015.
Mr Boock was reluctant to reveal his abuse as a teenager, fearing the consequences in Dunedin's tight Catholic community.
He eventually told a priest, who warned him he would be committing "a mortal sin'' if he did not speak out.
"Which, to my mind, was telling me I was going to hell.''
Mr Boock took months to find the courage, but eventually told Mr Pettit to stop or he would speak out, and the nightmare was over.
But the damage was done and a childhood of nightmares turned to alcoholism in adulthood, as Mr Boock came close to drinking himself to death.
Jobs and a marriage came and went, and Mr Boock was eventually admitted to hospital in 2008 and slipped into a coma.
A month later, as he started his recovery, he had to learn to walk again.
But then, while working in Christchurch in 2011, he received the bombshell - Mr Pettit was a teacher at St Bede's.
He contacted Mr Boyle, who took him to sign an affidavit in the presence of a lawyer.
Mr Pettit later admitted everything to Mr Boyle, but the school decided it was "a one-off thing in his life'' and took no further action, he said.
Mr Boock accepted the outcome, believing he had done what he could despite an "incredibly traumatic'' process.
He sent a bill for counselling to Mr Pettit, but declined other offers of help from the college.
But now, looking back, Mr Boock said he was "appalled'' by the college's response.
"He [Mr Boyle] enabled the institution, St Bede's, to harbour a self-confessed criminal.''
The Education Council has confirmed it is now investigating, after receiving a complaint from Mr Boock earlier this year.
Mr Boyle, responding to ODT Insight questions, confirmed "historic allegations'' made by Mr Boock had been investigated, following an established process, in 2011.
He would not comment on the findings, citing privacy, but stressed Mr Boock had accepted the outcome and thanked the college for having "covered all the bases''.
Mr Boock said that reflected his ill-health at the time, but the situation showed why all faith-based institutions needed to be part of the upcoming Royal Commission into historic abuse.
