Dementia CAD hyponatrinia hypothyroid.

Father My father age 77 has  vertical dementia for last 6 plus years . Have been consulting sr neurologist few times and started first time in aug 2016 ...donep 5 then increased to 10 mg a day It was very effective n he started doing normal like reading newspaper tv etc After 8 months around feb 2017 ..donep  stopped giving same results n he was irritated abusiveh when awake . Memory issue and difficultly in maintaining balance while walking. CT latest n MRI aug 2016 attached He had by pass surgery in 2008 with right carotid. Then in 2009 n few more time had sodium defiency na coming down to 104 in 2009. Post which he walked only with stick Now in aug2017 doc put him on donep 10. But he was sleeping or eyes closef atleast 20 hrs in a day. We consulted and he was put on admenta 10 twice last month in feb along with Amazeo 50 once . After admenta started.. he doesn't sleep 20 but 10 to 12 hrs . But last few days again he is sleeping 16 hrs around . Pls suggest if any change needed?