My Father Was Admitted To Hospital For Pneumonia Has CoPD.

My father was admitted to hospital for pneumonia has CoPD. He was moved from ER to floor. He was stable and alert talking when we left at 9:00 pm. At some point he was taken to a room. Within one hour after the nurse stepped out they found him blue without his oxygen. They did CPR is he on breathing tube sedated. We think he is responding to us opens his eyes. What are the chances of permanent brain damage? Could they remove breathing tube and can he survive or are they just extending his time with the breathing tube.