"When Michael died, a large part of me died with him," said Tammy Blankenship.
Blankenship blames the death of her 15-year-old autistic son on a medical mistake, and has filed a claim against Seattle's Children's Hospital and two dentists for more than a million dollars.
"To explain the sorrow this caused me and my entire family..." the mother said.
Autistic, Michael Blankenship couldn't speak or take oral medications. As a result, doctors prescribed a patch containing the powerful painkiller fentanyl following the March surgery.
The patch, which was placed on his back, is typically used on cancer patients or people with a narcotics tolerance.
"Clearly the dose was too much for this patient," said Dr. David Fisher, the hospital's medical director.
The head of Children's Hospital paid the Blankeships a home visit to personally apologize, but Tammy Blankenship said she has yet to hear from the dentist who prescribed the narcotic that proved fatal for her son.
"I can't bring my child back. I can't reverse the decision made to prescribe a drug that killed him," she said.
The hospital is not disciplining the doctor or the medical team, saying no one intended to harm the boy and, until now, there was no process to determine if fentanyl was being used for the right person.
"This occurred because our processes failed at multiple points," said Fisher.
"Not punishing somebody for killing my child is the most outrageous thing I've ever heard of," said Tammy Blankenship.
In the wake of the boy's death, Childrens' changed the way it prescribes and administers the patches, and now a pain management specialist must approve the medication.
But the changes are not enough to bring the mourning mother any peace.
"I am seeking justice for Michael," said Tammy Blankenship.
The family and the hospital attempted to settle outside of court, but failed to reach an agreement.