Subscribe to the Alzheimer's Daily News at  http://alznews.org - they have amazingly uplifting articles and advice. Find a geriatric specialist to assess your dad and the medications he's on - frequently behavioural issues are caused by interactions or bad meds (avoid Risperidone if possible - it is a "warehousing drug" used by many nursing homes to turn their patients into drooling masses of nothingness).  Check the Mayo Clinic website http://www.mayoclinic.com/health/drug-information/DrugHerbIndex  and http://www.pdrhealth.com/home/home.aspx for drug info. Minimize change if at all humanly possible as it is one of the greatest enemies of a dementia patient.  Best wishes and God Bless!