Is it forbidden for a mother to save for herself a portion of the money allocated for her children's needs?

A wife has the right to take from her husband's money secretly if he is stingy and does not spend on her and their children appropriately. However, if he does spend on them appropriately, then it is not permissible for her to take from his money without his permission; otherwise, it would be a forbidden betrayal. The daughter should advise her mother to repent and return the money to her husband, unless he forgives her.