Is it permissible to take from a father's money without his knowledge to help a needy person, on the condition that it be considered a debt?

The fundamental principle is the inviolability of people's wealth. It is not permissible to dispose of it except with their permission and consent, based on the Almighty's saying: {O you who have believed, do not consume one another's wealth unjustly but only [in lawful] trade by mutual consent} [Quran 4:29], and the Prophet's (peace be upon him) saying: "Indeed, your blood and your wealth are sacred to you, as sacred as this day of yours, in this month of yours, in this land of yours."

This prohibition is particularly emphasized for a child regarding their father's wealth, due to the potential for disobedience (disrespectful behavior) that might result from taking from his money without his knowledge. The intention to return the money does not permit taking it without the owner's knowledge. And your desire to help someone in need does not permit you to transgress against your father's wealth and take it without his knowledge.