There is Nothing Incumbent Upon You, Because You Did Not Intend to Kill Him

Question :

I am asking about an accident which occurred to me a year and a half ago. I used to love my father but family matters occurred between us, but in spite of these matters, I loved him and he loved me too, but because of these matters, we continually disagreed, every day. One day, my father became ill and entered the hospital. After he left, the doctor informed my mother that he must not be subjected to any problems, because they might affect his mood and cause his death, and because he could not bear any shock. Three months passed after his discharge from the hospital and my mother did not inform us of this. Then a problem occurred between him and I which made him angry with me. He had a shock on the same day from some other problems, then he was admitted to the hospital and he died. Now I am asking:
Was I the cause of this? And what is required of me by the Islamic Law?

Answer:

Nothing is required of you, because you did not intend to harm him, and you did not know about the problems which he was advised to avoid. So Allah Willing, there is no sin upon you. People always suffer from problems, and it is not possible to remain free of them. You are no different from other people in this regard, so there is nothing incumbent upon you, Allah Willing. There is no ransom required for you to pay, nor any atonement, because these matters normally occur between people: They occur between the father and his son and between brothers and between a man and his wife so there is nothing in this, Allah Willing.

Source:
Ibn Baz
Fatawa Islamiyah, Vol. 6 Page 182