Is it permissible for a mother to disclose her son's marital private matters to her other daughters without his knowledge or consent, under the pretext of finding a solution to the problem, and is this considered a disclosure of the son's private affairs?

A mother's disclosure of her son's secret among his sisters is forbidden and a betrayal of trust, based on the Prophet's (peace be upon him) saying: "If a man narrates a حديث (statement/story) and then turns around, it is a trust." The mother's excuse that there is no harm in it because they are his sisters is not valid, as every person has their own privacy that they do not wish anyone to know about. The mother must repent and seek forgiveness, and instruct her daughters to keep what they heard secret.