What is my duty toward my sister, and must I inform her that her husband earns unlawful money and commits immoral acts, knowing that he does not pray and does not fear Allah, and that she is psychologically ill and pregnant?

The answer elaborates on three points to address the issue:

1. Verifying the brother-in-law's actions: The accusations made against the brother-in-law must be verified, as the fundamental principle is that a Muslim is presumed innocent, and it is impermissible to accuse him without clear evidence.

2. Admonition and Preaching: If the husband's sinful acts are proven, he must be advised with wisdom and good admonition, focusing on the gravity of abandoning prayer and its consequences, such as disbelief and apostasy from the religion, as well as the danger of immoral acts.

3. Seeking Annulment of the Marriage: If the husband insists on abandoning prayer and committing immoral acts, then the annulment of the marriage is the solution, because one who abandons prayer is a disbeliever, and it is not permissible for a Muslim woman to remain married to him, nor is it permissible for her to remain with an immoral fornicator. One should not rush to convey these matters to the sister without legitimate Sharia evidence.