Tony Hudgell, eight, had both legs amputated after being abused as a baby by his birth parents, Jody Simpson and Tony Smith.
A Court of Appeal challenge, Justice Secretary Dominic Raab conceded, could not delay Simpson’s release any longer.
“We now just have to prepare Tony,” said Ms Hudgell, who has advocated for longer sentences for abusers.
In February 2018, Simpson and Smith were sentenced to ten years in prison.
Following Mr Raab’s admission that he could not successfully challenge a High Court ruling that quashed his decisions to refer Simpson’s case to the Parole Board, a senior judge ruled that Simpson should be released.
Ms Hudgell stated that she was unaware of Friday’s hearing until a victim liaison officer informed her of its outcome.
“I was shocked to hear she was going to be released,” she said.
Simpson’s release has been delayed pending the outcome of Mr Raab’s appeal.
Tony faces “daily challenges,” but is a “very happy, joyful eight-year-old,” according to Mrs. Hudgell.
She expressed her gratitude to Mr Raab and his officials for pursuing his bid to postpone Simpson’s release.
“I believe they’ve done everything possible to try to change things,” she said. “As a bonus, we appreciate every extra day she spent in prison beginning in August.”
Mrs. Hudgell of Kings Hill, Kent, has advocated for harsher prison sentences for convicted child abusers.
She is now advocating for a child cruelty registry in order to prevent those who abuse children from working with children.
Tony’s Law went into effect in June, which means that abusers could now face life in prison.