Hi Barb,
Being back home is likely to be a whole new world for your Dad. I think you can count on things being different and they may or may not get back to the "normal" you knew.
The other thing to consider is that there will come a time (if it hasn't already come) when you cannot give a person with AD a choice and let them choose. They cannot handle that or understand all sides of the issue. Your Dad may not be able to say where he'd like to live. He may get home and not think of other places. My mother didn't even notice when she was moved from her ALF apartment to share a room in a locked unit. She was content, perhaps restless, no matter where she was. It didn't cross her mind that she was in a new place and she didn't think to ask what had become of her apartment and her furniture. It seemed to me that her reality was only what she could see.
When the time comes for your father to return, perhaps you should revisit the sticky about the 7 stages so you can remind yourself what he was like when he left and read up on what might be next. You'll be more ready.
Wishing you well, friend! Barbara