Sorry to hear this, it must be distressing for you. Older dogs can suffer from dementia even when they're still physically fit, my first GSD used to get very confused in his old age and there have been several threads on here recently on the subject. Perhaps a word with your vet might shed more light? As long as Romeo's still physically fit, he can still enjoy a good life, with a few adjustments, but I'd advise a medical check up first of all, to try and pinpoint the cause.
All the best!