People with Dementia
& other intracranial insults like a Stroke
show significant alteration in their sensorium in response to fever, infection or alterations in their metabolic parameters .While there might be some natural progression in the Dementia there is likely to be superimposed Delirium
on his underlying condition. So it will be worth while to check his serum electrolyte levels,other correctable metabolic parameters and any source of infection & also maintain a strict control on his blood sugar.(also checking for urine ketones may be helpful)
If there is any correctable factors you might see an improvement in his general cognition and states of confusion.Going back on Glyburide
might not be that helpful as it was precipitating Hypoglycemia
. Hope this helps!