Does the non-obligation of maintenance for a disobedient mother mean that the father has a choice in spending on her? And is the son's action of taking an extra amount of money from the father to give to the mother considered theft? And what is the ruling on a father disclosing his wife's illness secret out of spite?

The success of married life requires understanding and overlooking [faults]. Children should strive to mend their parents' relationship through prayer and wisdom, and by preventing the oppressor from his oppression. A disobedient wife (nashiz) is not entitled to maintenance according to the majority of scholars, but it is better for the husband to spend on her. It is impermissible for a son to lie and accuse his father of stinginess. He is permitted to take from his father to spend on his mother or on himself, so that he may economize and save for her. A father should not disclose secrets. Parents must be convinced to compromise and show understanding.