Is it permissible to dispose of the husband's money by giving charity and gifts to one's mother without his knowledge? Is it obligatory to return gifts to parents if the wife does not possess her own money? Is it permissible to take the husband's money to purchase necessities from one's parents based on their request?

It is forbidden for a wife to dispose of her husband's money without his permission, except for a small, customary charity, or taking the obligatory maintenance if he withholds it from her.

Your donation of your money to your husband or its being a condition for your work does not permit you to take from his money without his permission, unless you gave it with the intention of retrieval, in which case you have the right to demand it back, but not to take it without his knowledge, except in the matter of "al-Dhafar" (seizing one's right).

Paying for your parents' purchases from his money without his permission is not permissible.

You must repent to Allah and seek absolution from your husband by asking for forgiveness or by returning the money you took unjustly.