My husband was diagnosed 14 years ago with sleep apnea. He has had surgery and wore the C-PAP before that. He has not had major difficulty until the past 6 months. He has been re-evaluated and now is using a new C-PAP for a week.   He is sleeping less, about 4 hours, each night.   I am concerned about his oxygen levels and the inability to think clearly about daily functions.   He is 59, 6', and 200 #.   He does not smoke and will have a beer once in awhile. He has been taking Levitra. I am wondering if this is a good choice with his condition. What other treatment is there available? Should I be concerned about other medical problems? Thank you for your suggestions, Linda