Is it permissible to inform the husband of the secret of the miscarriage that the mother promised to keep, and how can one overcome the grief of losing the miscarried brother/sister?

First: Fulfilling trusts and safeguarding secrets is a religious obligation, as indicated by the sacred texts, and there is no distinction between a believer and a disbeliever, or a righteous person and a transgressor. This right is further emphasized if the secret's owner is a relative, especially the mother. Therefore, you must safeguard your mother's secret and what she has entrusted you with.

Second: To get rid of disturbing thoughts about losing a brother or sister, there are two approaches: 1. The Religious Approach: Believing in Allah's divine decree and destiny, and that what befell you was not meant to miss you, and what missed you was not meant to befall you. All calamities are written in the Preserved Tablet, and this prevents sorrow over what has passed and arrogance over what has come. 2. The Psychological Approach: If these thoughts persist with symptoms of tension and anxiety, it is advisable to consult a psychological specialist for a deeper understanding of the problem and to offer practical solutions.