Warmbier said recently, they made a decision to go public with their situation and shortly thereafter, Otto was home.
They say he does not show any consistent response to stimulation, shows no sign of understanding language, responding to commands or awareness of his environment.
North Korea did not comment on Warmbier's medical condition or how his release was negotiated. Others want to know why he was in North Korea in the first place. An analysis suggests the injury likely occurred in the preceding weeks.
"We've been brutalized over the last 18 months with misinformation, no information", he said.
Otto Warmbier was in a coma when he landed in Cincinnati late Tuesday night.
The cause of Warmbier's condition remains uncertain.
The college student was sentenced that March to 15 years of hard labor for theft and spent most of his imprisonment in a coma, according to his family.
If you want the details leading up to his coma, then find out with our Otto Warmbier wiki.
"We're going to leave that to the doctors (to explain) today", he said.
Joseph Yun, the U.S. State Department's special envoy on North Korea, traveled to Pyongyang and demanded Warmbier's release on humanitarian grounds, capping a flurry of secret diplomatic contacts, a U.S. official said Tuesday.
Otto Warmbier, 22, returned to OH on Tuesday after being detained and imprisoned for 18 months in North Korea.
He said he felt "anger that [Otto] was so brutally treated for so long" but was relieved his son was "now home in the arms of those who love him".
The doctors declined to discuss treatment for Warmbier or his prognosis, citing the family's wish for privacy.
The elder Warmbier gave a press conference Thursday wearing the same jacket that his son was photographed wearing at his last public appearance in March 2016, when he delivered a tearful - and likely scripted - confession to stealing a propaganda banner from his hotel in Pyongyang.
That was used as evidence in his hourlong trial.
The father of a USA university student repatriated in a coma this week after being held in North Korea for 17 months says his son was "brutalised and terrorised" in custody.
Warmbier took questions from the reporters, many of whom asked about Otto's well-being.
They kept quiet "on the false premise that (North Korea) would treat Otto fairly and let him go", he said.
North Korean officials reportedly told Mr Warmbier's family on his release on Wednesday that he has been unconscious since contracting botulism and being treated with a sleeping pill.
Fred Warmbier called on North Korea to release other American detainees.
Fred Warmbier also offered some criticism of the Obama administration.
The father saluted his son as a brilliant, adventurous and courageous man who did what he could to endure brutality and terror.
He left the vehicle and spoke to the crowd.
"I'm not confessing; I'm speaking", he said.
The university student, who had been on a tourist trip, was sentenced to 15 years hard labor, a punishment the USA decried as far out of proportion to his alleged crime, accusing the North of using him as a political pawn. The former basketball star's trip was a "distraction", he said. Warmbier said, "Otto was held as a war criminal".
"Otto is a fighter", he said.