What Is The Life Expectancy When Suffering From Vascular Dementia?

my husband is 67. he has had four interval hemorrages, three on left, most recently one on right. He has vascular dimentia and amyloid angiopathy. He is under constant doctor care, at this point, medications and controlled blood pressure. I dont have the courage to ask the doctor, but I need to know, what is the usual life expectancy at this point.