He could be losing his vision. Did your vet check? As our lab mix got older, same thing happened. Doc says she sees shadows and hears noises and cannot figure out where they are coming from. Peripheral vision goes first. She has lost most of her vision now, and her hearing is going too. According to our vet, we should keep her in her element and make things as stressless as possible. Her mind starting going two years ago in November, and she goes through her dementia loops. We just try and keep her comfortable and safe. Good luck. We certainly feel for you.