
I would like to know that if a husband in his lifetime have not cared for his wife or children in any way. Nor earning a bit, nor looking after the children or helping his wife in anything in anyway, Instead harassing them. So in this circumstances if the husband passes away. Is it compulsory for the aged wife to sit in iddah. Please explain in detail under the Islamic ruling.

Bismillahi Ta’ala
Walaikum Assalam Warahmatullah,
If he scenario mentioned in the question not hypothetical, then first and foremost I sympathize with the wife.
That being said, Islamic laws and ahkam of Iddah are attached to the divorce or death in a married couple. They are not affected by the treatment or abuse thereof by the husband or wife in the said marriage.
Thus, while the husband’s actions mentioned in the question are madhmoom (rebuke worthy) and regrettable, the iddah laws will still apply.
The iddah of a widow is 4 months and 10 days (lunar months) from the date of the death of the husband. Thus if the husband passed away on the first of Islamic month, then waiting period will be 4 Islamic months and 10 days. If, however, he passed away on some other day of the month then the wife will be count 130 days for her waiting period.
If you require full rules of Iddah, please do let me know. Jazak Allahu Khairan.
Wallahu A’lam
And Allah Ta’āla Knows Best
Mufti Faisal al-Mahmudi