As above, with this type of symptoms there could easily be a bit of dementia or something going on in the brain, or liver/kidneys could be deteriorating and toxins could be building. A diary is perfect to see exactly what he is doing and how often.
There are medications that can help with dementia, or natural based supplements that can support brain function with omega 3/6 balance, antioxidants and the like.
If you think his quality of life is fine, then monitoring and keeping a diary is the first step, if you worry he is getting distressed by not quite knowing what is going on, a vet visit may be in order. The vet certainly should always listen to your concerns and offer testing such as bloods, neurological examination and/or treatments as required.
Don't feel silly, owners always know their pets better than the vet can, so any change is worth looking into.