Hi, My Father Is Hospital And His Is Very Tired

Hi, my father is hospital and his is very tired and need oxygen to breath. The doctor can't find any problems and now they want to cut a piece of his lunge off to see if there is any other problems. If they find nothing, he needs to be on oxygen the rest of his life. I need advise if there could be anything that can cause this or what to do to make it beter.
Thanks