REDWOOD VALLEY, Calif. -- A teenage girl died in a hospital three weeks after she was severely burned in a fire that tore through Mendocino County, California, raising the number of those killed in the state's wildfires this month to 43.

Kressa Shepherd, 17, died Sunday night at a Sacramento hospital, her aunt, Mindi Ramos, said Monday.

Ramos said doctors at Shriners Hospital for Children noticed Kressa did not register pain during a change of the dressing on her burns and after performing a CAT determined she was brain-dead.

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"They kept her alive so we could say goodbye and eventually stopped the machines that were assisting her," Ramos said.

A neighbor found Kressa, who was a junior at Ukiah High School, and her mother lying on the ground outside their home in a rural neighborhood in Redwood Valley. Both had more than half their bodies burned.

Kressa's brother, 14-year-old Kai Shepherd, was found dead. He is among the youngest who died in the wildfires.

First responders found their father, Jon Shepherd, separately, on the mountain. He was also badly burned but alive.

The Shepherds apparently tried to outrun the flames as the home their father built burned down.

Sara, 40, and Jon Shepherd, 44, remain hospitalized and have gone through several grafting surgeries.

Sara had burns in over 60 percent of her body and is at UC Davis Medical Center, in Sacramento. Jon was burned over 45 percent of his body and is hospitalized in stable condition at St. Francis Memorial Hospital's burn unit in San Francisco, Ramos said.

She said her sister and brother-in-law are conscious but only talk in whispers and have not asked questions about what happened.

"We don't know how much they remember from that day but we were advised to not give them the tragic news about their children unless they ask," Ramos said.

She said her family is staying strong for her sister.

"Her entire life has been devastated and we're just taking it one breath at a time, one minute at a time," Ramos said.

The wildfires that started the night of October 8 and swept across a wide area north of San Francisco are the deadliest and most destructive the state has ever seen. While much of the devastation is in Sonoma and Napa counties, the heart of California's wine country, fire also wiped out a swath of Redwood Valley, a community of about 1,800 roughly 70 miles north in Mendocino County.

Firefighters expect to fully contain the fatal fires that destroyed nearly 9,000 homes and businesses this week.

Meanwhile, state emergency services official Eric Lamoureux set a target of early 2018 for completing the clean-up and allowing owners to start rebuilding.

"The size and scope of this debris removal process will be one for the record books," Sen. Mike McGuire, a Democrat from the wine-country town of Healdsburg, told fire survivors at a Santa Rosa community forum. The meeting gave residents some of the first briefings on the clean-up to come.

Authorities have warned residents returning to the ruins of their homes to beware of possible hazardous residues in the ashes, and required them to sign forms acknowledging the danger.

In Sonoma County, the scene of the most destruction and deaths, county officials will draft environmental standards to be followed by any homeowners who opt to handle the clean-up themselves, at their own expense, officials said. For property owners who let the government handle the clean-up, taxpayers will cover any of the costs of debris removal that insurance doesn't, Lamoureux said.

In addition to destroying homes and other buildings, the fires also caused extensive damage to vineyards, CBS News' Adriana Diaz reported.

A Napa Valley trade group says 90 percent of this year's grapes were harvested before the fires started.

The wine tourism industry here has also been impacted but tasting rooms, hotels, and tour bus companies want people to know they're still open.