McMath, 13, began bleeding from her mouth and nose after the operation and later went into cardiac arrest. She was placed on a ventilator and then experienced swelling in her brain. A few days later, she was declared legally brain dead.
The girl’s family thinks that Children's Hospital Oakland could have done more.
"There was a lack of urgency," said McMath’s 27-year-old uncle Omari Sealey. "It's shock, it's disbelief. You never think something like this will happen to you."
Her grandmother, Sandra Chatman, said it "felt like somebody stabbed me in the heart. They took away my granddaughter. That's how it feels.”
The family has asked that McMath be kept alive.
"As long as she has a pulse, we want her on life support," Sealey said. "We want her to come home for Christmas. We want to give her presents. We want a chance for a Christmas miracle."
Hospital spokeswoman Melinda Krigel said "the hospital is very, very sad about this outcome. It's incredibly sad. What I can add is that there is informed consent that comes with any surgery and that with any surgery, there can be unanticipated outcomes."
Prior to going under the knife, McMath took off a pair of pearl earrings and gave them to her grandmother. "It's so hard to look at them. I get choked up," Chatman said. "I'll keep them for a lifetime. In every purse I carry. They will always be with me."