Hello, The description provided by here regarding your grandfather is highly suggestive of Dementia which is a significant lowering of mental and neurological functions. Hence you can help your grandfather in the following manner- 1. Consultant a neurologist or a psychiatrist near you for comprehensive assessment. 2. Detailed assessment including investigation like MRI, blood etc will be required. 3. Treatment will be initiated to retard the progression of disease, and behavioral issues. 4. If the cause is found to be related to reversible dementia, the cause will be corrected. 5. Your family will be helped in caregiver role by some education and training. Hence please do not delay in seeking help. Hope this helps you. Best wishes for your health and future.