What they didn't know was that embers had fallen through cracks in the fireplace and the underside of their floor was already burning.
Mr de Souza fell asleep on the couch but was woken when his hand became hot. He realised instantly that the fire was burning under the house and in the wall cavities.
He yelled out to his wife, waking her, and they grabbed 2-year-old Matias and 1-year-old Memphis and ran.
As the house become engulfed in flames - within five minutes - they stood outside clutching their still-sleeping children.
They fleetingly considered moving the family car which was parked close to the house. Within seconds the car was being licked by flames, then the boom of the exploding petrol tank added to the sounds of the raging fire.
"Now it seems like time was speeding up and slowing down during it," Mrs de Souza said.
"We were just standing there watching this thing happen. I was in pyjamas and no shoes, the boys were in their night stuff, Rui was dressed ... and that is all we have now, literally nothing but the clothes on our back."