PORTLAND, Ore. — A mom and son who were critically burned in a southern Oregon house fire Wednesday morning have died, according to the Multnomah County medical examiner.

Tabitha Annette Howell, 38, and Andrew Hall-Young, 13, died Thursday evening at Legacy Emanuel Hospital in Portland.

The fire previously claimed the lives of four other children, 4-year-old Gwendolyn Howell, 7-year-old Haley Maher, 10-year-old Isaiah Young and 13-year-old Nicholas Lowe.

The remaining survivor, 39-year-old James Keith Howell, was in critical condition in the burn center, a spokeswoman for Legacy Emanuel Medical Center in Portland confirmed on Thursday.

The Howell, Hall, Hendricks and Young families released the a statement on Friday:

The families have decided to donate Tabitha Howell and her son Andrew Hall-Young's organs to give the gift of life to others. Again, they appreciate all the prayers and offers of support from everyone and are forever grateful. At this time, funeral arrangements are being made.

The love and support the family has received from the doctors, nurses and the support staff at Legacy Health Oregon Burn Center has been tremendous. We want to thank all of you for all you have done for us during this tragic time.

A volunteer fire chief in Riddle, Oregon, a tiny town with a population fewer than 1,000 people, said the fire started with a portable space heater that was being used after a fireplace malfunctioned.

Combustible materials placed too close to the heater ignited and started the blaze in the tiny timber town of Riddle, Fire Protection District Chief Rich Holloway said in a post on the district's Facebook page.

Holloway did not immediately return two calls but City Manager Kathy Wilson confirmed the authenticity of the Facebook post in a phone interview.

A component of the fireplace that forces heated air back into the home malfunctioned several days before the blaze early Wednesday and the family was using the heater until they could get it repaired, Holloway wrote.

"All the burn pattern indicators, witness statements and the statement from the father on first arrival, all collaborate," he said.

Some members of the all-volunteer fire department knew the family, Wilson said.

"In a small town like this, everyone knows each other and this has been devastating," she said. "It is just such a tragedy. It's something we've never seen before. It has affected everyone."

Community members held a candlelight vigil at a church late Wednesday that attracted more than 300 people.

Grief counselors were on hand at schools in the South Umpqua School District, where some of the children attended class, said Superintendent Tim Porter.

The district has just 1,450 students in all grades, he said.

In a statement released through Legacy Emanuel, family members huddled at the survivors' bedside declined interview requests.

"The community has been so generous in their response to our needs with prayer and offers of support, and we are very grateful," the statement read.

"At this time, we are requesting continued prayers and your respect for our privacy, as we are grieving our loss."

Family members set up a Gofundme page for the family's medical bills and funeral costs.