I go see my dad once a week most times. 3 or 4 weeks ago he had some kind of flu or cold and the staff at the nursing home said there is no sense me going to see him because he was mostly in bed sleeping. So I skipped one week of seeing him. When I went to see him the following week, he seemed lethargic and very weak. So I thought maybe he was still feeling the affects of the flu or cold. I didn't stay long. Then I went again a week later and he was even more lethargic. He kept staring off into a corner and speech seemed very difficult for him. Is this a normal progression of the dementia or could this be caused by medications?