high co2 level

My mom was rushed my ambulance to local ER last week, and a blood gas was drawn with a result of a co2 level of 142! She was unconscious. They did not give her much hope to recover, but put her on a bipap. The attending physician said it would not be likely that the bipap would bring down the co2 level, but he was wrong. We had her transferred to a major hospital and that is the therapy they used to lower the co2. She is still in the hospital, and her co2 level is now 70, which is still considered critical, but she is awake, talking, and seems fine. The doctor said he would explain later how this could have happened to her. She does have advanced bronchiectisis. Would she benefit from wearing a cpap or bipap at night? She has already had a sleep study and diagnosed with sleep apnea, however she could never tolerate wearing a cpap, so we sent it back to her respiratory care provider.