I'm worried about my dad's health. He's talking slower this year. How to increase brain blood flow?

PMD & Neurology. Aging alone should not slow speech. Has your dad had a stroke? How old is he? What medical issues does he have and medications is he taking? These can be implicated. Best to go to a doctors appoitnment with your father to discuss this concern. It may be worthwhile for a neurologist to examine your dad as well. Good luck!