The fire broke out about 7:45 a.m. Wednesday, while 10 people were inside the house, WJHG-TV, Panama City, reported.
Six children survived the fire, while four women were unable to escape.
James Rhynes said the deceased were four of his relatives.
"My grandmother, her name is Gertrude Pete. Her mother, which is Sarah Johnson, that's my great grandmother, and then my mother's father's mother, Elise Pete, [who] was also in the house, and then my mom's baby sister who was also in the house, Cynthia Pete," Rhynes said.
Marianna Fire Chief Nakeya Lovett said fire alarms in the house woke up six children, all under the age of 8.
"That's what woke them up to alert everybody that there was a fire to try to get everybody out. And unfortunately the four didn't make it out. These women were pillars in the community. A lot of people would pass by and blow the horn as they saw them sitting on the porch. It's just heartbreaking," Lovett told the broadcaster. "They did what they could to try to save the individuals. But we got the call, unfortunately, a bit too late and had four fatalities."
The cause of the fire was under investigation.
"Right now we're speculating that it came from an overloaded extension cord," Lovett said.