An 8-year-old boy who died with his father in a Dacula house fire Wednesday morning may have saved the lives of his mother and sister.

Michael Cash was the only person who was awake when the fire broke out in the den of the house, in the 2000 block of Crowe Road, said Gwinnett Fire Department spokesman Tommy Rutledge. Michael alerted his parents and sister, who were asleep when the fire started some time after 8 a.m.

The father, 73-year-old Les Cash, died as he tried to extinguish the fire. His body was found in the den. Michael was found in a bedroom; he was taken to Gwinnett Medical Center, where he was pronounced dead. Both victims suffered smoke and burn injuries, Rutledge said.

Rutledge said neighbors called 911 when they saw flames coming from the house. When fire crews arrived, the one-story wood frame house was "well involved," he said.

Jessica Bailey, a niece of the Cashes who lives next door, said the mother, Debbie Cash, ran to her house for help, but by the time they got back to the house the flames were too intense to enter.

A passerby who saw the flames broke out a window air-conditioning unit and he and Debbie Cash rescued the couple's 6-year-old daughter, Catherine, according to Bailey. The mother and daughter were taken to Gwinnett Medical Center for evaluation. They were both listed in stable condition, Rutledge said.

Les Cash was a retired Army veteran, Bailey said. He had also worked for the DeKalb County school system, she said. Michael would have been a second-grader at Harbins Elementary School.

Sheila Lynch, a neighbor, called the children "two regular kids who loved to play with my kids ... It's just a devastating tragedy."

The fire started in the den, but the exact cause of the fire has not been determined, Rutledge said. He said there were no working smoke detectors in the home.

-- AJC photographer Vino Wong contributed to this article.