What Causes Memory Loss And Night Terrors Inspite Of Having Collapsed Lungs?

Question: My father recently had a ruptured and collapsed lung. When he arrived at her his oxygen level was 68. He underwent a surgery in which they attached his lungs to his chest cavity. He is now on full time oxygen. During his first hospital stay we thought his behavior was due to the pain meds. He Is currently in hospital without those drugs and the same behaviors are occurring. He forgets what he's trying to say, he is talking to somebody who is not there. He believes he's a prisoner and they are after him and we need to help him get out. When he is home he does not do this. However he does have night terrors and lately he wanders at night and some times forgets where he is. He sees things that are not there. But if you ask his name or birthday things like that he is very aware. Is it possible the lack of oxygen did any long term damage? Are there certain tests that should be ran when w a small at such low level of oxygen for some time? He is also a Parkinson patient. Could this be signs of dimentia? I feel as if half his problem of feeling breath less isn't just because of what he went through but because extreme anxiety possibly causing panic like attacks. Any advice would be appreciated. Do anxiety mess or sleeping meds interact with any medication that he Is currently on? Here are his meds Famotidine, ranitidine, proair, Carbidopa,Tolterdine, Symbicort, albuterol,Pantoprazole