Published: Aug 30, 2010 11:59 PM EDT
Updated: Aug 30, 2010 8:56 PM EDT

LEE COUNTY, Fla. - Rosemary Kunz admitted she was addicted to abusing her young stepson. She'll spend 18 years behind bars.  

She entered a surprise plea deal for the abuse that almost killed Kaydin Matheisen.

At the time of the abuse, doctors gave the toddler a ten percent chance of survival.    

"I do not want anyone to think this was a walk in the park. Its been a journey through hell," said Shane Lewis, the victim's father.

He held back tears as he read a victim impact statement to the court. He says his now four year old son Kaydin will never recover from Kunz's abuse.

"His smile is still lopsided but atleast we can kiss him at night," said Lewis.

The four year old will have to take seizure medication for life and continue physical therapy. He still can't hold a pencil at school because of the brain damage.

The family is happy with the 18 year prison sentence. Lewis says Kaydin will be an adult by then, and Kunz will never be able to hurt him again.