What Causes Anger And Fainting?

Hi!! I have ahuge problem. I'm a 1 yrs old girl and i have 3 siblings. My father is the one with the problem. My dad is always angry, yelling, cursing, or mad. I don't know why but he is. He faints whenever he's mad or randomly sometimes. We have to wake him up after it happens. sometimes, he doesn't wake up for a few minutes. What is wrong with my father? place help.