A woman was killed and a man was seriously injured during a house fire in northwest Houston early Sunday morning, authorities say.

Celia Estrada, 77, was found deceased inside the home by firefighters who responded to the overnight fire.

Her son, Francisco, 53, was severely burned and was taken to Memorial Hermann Hospital in critical condition.

Neighbors say Francisco is Celia's oldest son and did all he could to save her in the blaze. Over half his body was burned trying to get to his mother inside the home.

“The words that I heard from him exactly were 'My dog and my mom are inside,” said Allexa Smith, a witness. “My mom and my dog are inside.”

According to neighbors, Celia was a widow and had dementia. They said her son Francisco was her caretaker and rarely left her side.

Theo Smith, Jr., one of the neighbors, said he and Francisco went to school together, elementary through high school, and played softball together. He said Francisco still plays in a 50-plus league.

Smith, Jr. said Francisco never moved away from home because he wanted to take care of his mother and look out for her aging neighbors.

“(Francisco) could see my dad trying to get in the car, trying to do something or pick up something and he would jump up and run just without questions or answers,” Smith, Jr. said. “'Hey, I got it Mr. Smith. I got it.'”

According to the Houston Fire Department, they received the call around 2 a.m. about the fire at the home located in the 6600 block of Granite Street.

Fire crews arrived to heavy flames and smoke. Images from the scene show damage to the right side of the home's front.

HFD Arson is still investigating the cause of fire.