Is one who bore false witness, at the age of twelve and under duress from his murderous father, to his sister's suicide considered sinful now that he is in his thirties? And is he obligated to bear truthful witness against his father?

A man killing his daughter is a reprehensible crime. If his son is certain of this, he must inform the authorities, for Allah has commanded the establishment of testimony, and has condemned and warned against concealing it, saying: "And conceal not the testimony, for whoever conceals it, his heart is indeed sinful," and by His saying: "And let not the witnesses refuse when they are called."

Therefore, it is not permissible for a Muslim to conceal truthful testimony, especially if failure to render it leads to the loss of a Muslim's life, property, or honor. An exception to the obligation of testimony is when the witness fears harm to himself, his body, his property, or his family, based on the saying of Allah the Almighty: "Let no scribe be harmed or any witness," and the saying of the Prophet, peace and blessings be upon him: "There should be no harm or reciprocating harm."