Is it permissible for a father to take whatever he wishes from his son's money without needing it, and is it permissible for the son to take from his father's money without his knowledge to the extent of his need?

It is permissible for a father to take from his son's wealth what he needs, provided it does not harm the son. It is permissible for a son to take from his own money that is with his father, whether with or without his father's knowledge. However, a son taking from his father's money without his knowledge is not permissible, unless the father is miserly in providing necessary support for his son, in which case the son may take what suffices for his needs if he has no money.