His sister was taken to Rotorua Hospital, but later discharged.
Witnesses told the Herald Frank Tamati burst from the house with Edwina in his arms, before Rangitihi dived through a window, receiving severe lacerations to his back and arms from the smashed glass.
Cousin Julius Tamati said he woke to the sound of screaming and ran across the street to see Rangitihi falling to the ground, with smoke fuming from his body.
"I said to him, 'What's happened, what's happened?' ... He sort of talked and then rolled over. There were cuts, he was just bleeding everywhere ... and his shirt was melted to his body."
Julius tried to calm his cousin, who could not speak but remained conscious until he was lifted into an ambulance.
"Then ... he just started crying. His face was burned pretty badly."
Neighbour Aroha Wharepapa was also woken by screaming and quickly realised it was Frank Tamati calling her name.
She said Rangitihi was in anguish, believing his two younger brothers were trapped inside. In fact, they weren't home.
"It looked like he was trying to get back in - we weren't sure if the other two were still in there, because the whole house was on fire and the windows were exploding," she said.
"I had to keep them away ... There's nothing he could have done if they were in there anyway."
Ms Wharepapa said that as she took Edwina from Frank Tamati, she didn't realise how badly Rangitihi had been burned.
"It wasn't until we were all out here that I thought to ring for help. I could see Rangitihi was in a bad way, but because it was dark I didn't realise that what I thought were clothes hanging off his arms was his skin.
"He did really well ... He couldn't talk but I think he was more stressed at that point because he believed he couldn't get to his brothers."
Other family members went to the destroyed house yesterday and were rallying around the whanau.
"We are all pretty shocked," cousin Tui James said. "A van load of his family, all the aunties, they've all gone to see him."
Fire investigator Stuart Craddock said the cause of the blaze, which was not suspicious, would be confirmed this week.
Meanwhile, a 34-year-old man is recovering in Waikato Hospital's burns unit after suffering severe burns to his arms in an Opotiki house fire on Saturday morning.
Eastern Bay of Plenty fire safety officer John Rewi said the blaze was started by a 3-year-old boy playing with a lighter.
