It was just in time, as there was no air pocket surrounding Nathan.
"He was fully encapsulated in sand," Miller said, noting it took about five firefighters to pull him out.
Once the family heard the boy was bleeding, Reul said, "Hope began to bubble up ... that Nathan's not gone."
He was airlifted Friday night to the University of Chicago Medicine Comer Children's Hospital from an Indiana hospital.
"I expected him to arrive much sicker than he did," said Koogler, medical director of the pediatric intensive care unit.
Nathan was sedated so doctors could remove as much of the sand in his lungs as possible. She said Monday doctors don't see any more sand particles but believe some are still in there.
Doctors also said early neurological tests didn't reveal any brain damage; Nathan can move his arms, legs, fingers and toes. Koogler also said Nathan's eyes appear to be fine, adding he must have had closed them while buried in the sand.
She said the biggest concern remains the boy's lungs, telling reporters Monday that Nathan could develop asthmalike symptoms in the months to come but that the injury to his lungs was "not nearly as severe as I expected it to be."
Koogler said if Nathan continues to recover at the same rate, he would likely be taken off the ventilator by the end of the week and released from the hospital in 10 to 14 days, but may need another month in a rehab facility.
In six months, she said, 'I'm hoping that he's going to be acting like a normal 6- to 7-year-old, riding a bicycle, doing what a normal 6- or 7-year-old does."
Reul said that before he and his wife heard anything about his grandson, he experienced sharp, stabbing pains in his chest. Reul was not ready to say Monday that those pains happened at approximately the time his grandson fell into the sinkhole.
But he was sure of what happened after: "It is a miracle."