Is it permissible for a woman to visit the doctor while in her `Iddah(waiting period)?
It is permissible for her to do that during day time, but it is impermissible for her to go out at night except for a sound reason.
Is Zakah(obligatory charity) due on rented property, and how is it calculated?
Zakah isn`t due on the rented property itself, but on the saved income from that property if it reached Nissab(minimum amount liable for Zakah), and a whole lunar year had lapsed over saving it.
Is it permissible to single out Fridays, Saturdays, and Sundays to make up for missed fasting without fasting a day before ,or after each ?
Yes, it is permissible to make up for missed fasting during the aforesaid days, and it is also valid to offer non-obligatory and vowed fasting as well. However, fasting a day before or after each isn`t obligatory.
I married a man and had two children; however, we got separated four years ago. In addition, my husband`s brother, paternal uncle of my children, has been providing for them ever since. In fact, he is an honest, well-behaved man. Is it permissible that we get married although his brother (My ex-husband) is still alive?
All perfect praise be to Allah the Lord of The Worlds. May His blessings and peace be upon our Prophet Mohammad and upon all his family and companions.
It is temporarily prohibited for a woman to marry her stepbrother. Therefore, once she receives Talaq Ba`in (Irrevocable divorce), she is allowed to marry her stepbrother, even if his brother (First husband) is still alive. And Allah The Almighty Knows Best.