My Scruffy is 15 and I find he does the same thing.

He used to sleep on the foot of my bed. Then he chose to sleep on his bed next to my bed. Now he sleeps on the floor next to his bed. Yet he can and will jump into the recliner sometimes for a nap. Once in great while I will wake up to a bed partner. So I put a step next to my bed to give him a choice.

I too, had a dog with doggy alzheimers. He was sent to the Bridge just a year ago. It was harder to deal with than any physical ailment.