I am so sorry you've gone through this for so long I am sorry that your father lost his father but it is inexcusable that he blame you for that! That blame has left indelible scars in you. He definitely needs therapy if he is not already getting it.
I don't know if you have a pdoc or T, but hopefully you do have someone because this obviously has eaten you up inside.
And no, you're not a curse. Thousands of people die everyday for a million different reasons. Death is a part of life.
Again I'm so sorry this has happened to you.

Z