Originally Posted by Elisabrat
at least 3-5 times per night when your really sleeping he makes a noise
Well, it sounds like you are going through what new moms go through with babies at night. Since animals tend to curl up and go to sleep when it is completely dark, you might try kenneling him in a completely dark room when you go to bed. Of course, that means you'll have to get up as soon as it gets light and let him out, but it's worth a try. As long as he can go for several hours without soiling himself, that is.
There are meds for cats that can improve cognition. Here is a good reference article:
http://cat-care.suite101.com/article...ave_alzheimers
My heart aches for you, because I know that it's a matter of how long you can hang on. And no matter how or why, it's hard to lose one. Hugs to you.