Is it permissible for daughters to give their mother money that their father had designated for them for charity (sadaqah), without his knowledge?

The husband is not obligated to give his wife from the salary allocated to him and his wife. Rather, he should spend on her in a reasonable manner (bil-ma'ruf). However, if the granting authority allocates a salary to the wife, it is her right, and the husband is not permitted to take it except with her consent.

As for what he gives to his daughters for charity, they are obligated to spend it in charity. They may give charity from it to their mother without their father's knowledge, unless the father stipulates otherwise.

If the father takes the wife's right from the social security (al-dhaman) without her consent, then the daughters may give their mother her right from the money the father gives them for charity, without his knowledge.