Have not heard of that syndrome.
But I read recently that “water on the brain” (hydrocephalus) can cause dementia, but may be treatable with surgery.
Highly recommend that you take him to a neurologist, preferably to a neurosurgeon, have him order an MRI and do an assessment.
Macular degeneration is a disease of the retina of the eye. Serious, but it does not cause dementia. Take him to a retina specialist, it may be treatable with laser surgery, depending on how advanced it is.
My grandmother had normal pressure hydrocephalus. Her dementia was seeing me as five different people interchangeable and she was always looking for some imaginary home. I was young in nursing school and had no idea what to do. But then took her for an MRI then a neurosurgeon and they placed a lumbo-peritoneal shunt in her lower spine draining the fluid and within 36 hours she was back to normal. The whole year and a half she had the dementia was like a dream to her and I never spoke of those times.
Charles Bonnet Syndrome is a bit different and never saw a patient with it but agree with the suggestion maybe a neurosurgeon/neurologist might be able to help?