Is it permissible to take money from one's father secretly to cover study expenses and personal needs that the father covers only with difficulty, and what is the ruling on disposing of the remaining money?

A father must financially support his poor children, both sons and daughters, providing for their food, clothing, shelter, and the expenses of studying communal obligations (fard al-ayn). If he falls short in this, they are permitted to take it without his knowledge. However, the expense of studying beyond that is not obligatory for him, and it is not permissible to take it from his wealth without his permission. Anything taken in excess of the necessary support, which he did not consent to, must be returned.