Is it Sharia-compliant to demand that my father disclose his possessions before a court, after he threatened to disinherit me and refused to give me a copy of the paper I signed, and what is the ruling on that?

The father who commits forbidden acts should be advised with wisdom and good counsel to save him from the Fire. If the father persists and it is highly probable that he intends to harm his child through a signed document, there is no objection to politely requesting him to disclose it or to seek the mediation of relatives. If that does not help, there is no harm in referring the matter to the judiciary, and this is not considered disobedience to parents. However, it is not the child's right to demand that the father disclose his possessions, and the father's wrongdoing does not negate the duty to honor him. Rather, one should respond to wrongdoing with kindness and compassion towards him.