What is the optimal course of action regarding the sudden disappearance of the husband and his refusal to communicate, while being pregnant and his family attempting to take the child, and his sister and first wife spreading rumors of divorce, whereas he affirmed to my paternal aunt that he has no intention of divorcing her?

As long as the husband is of good character and kind in companionship, it is better to be patient and find excuses for him. If there is fear that he might divorce you, then it is permissible to forgo some rights, such as maintenance (nafaqa) and equal division of time (qisma), if that will prevent the divorce; for Allah Almighty says: "And if a woman fears from her husband high-handedness or desertion, there is no sin upon them if they make terms of settlement between them, and settlement is best." It is also advised to maintain remembrance of Allah (dhikr) and recitations (ruqyah), along with reliance on Allah and frequent supplication.