I work in an accounting and auditing office, and among the clients of the office are restaurants, hotels, and supermarkets that sell alcohol. Our work is limited to collecting invoices, whether purchases, sales, or expenses, and recording them in daily books. We also review income and sales taxes on behalf of these clients.
You are more knowledgeable about the nature of your work. If you see it as assisting in wrongdoing, then it is forbidden, as Allah The Exalted Says (What means): "And cooperate in righteousness and piety, but do not cooperate in sin and aggression" [Al-Ma’idah/2]. However, if your work is merely documenting the reality, then I hope there is no sin upon you. The the pious predecessors (Salaf) used to take the tithe from the traders of the People of the Book, even if it included alcohol, after knowing the value of their goods. And Allah The Almighty Knows Best.
What is the ruling on determining the sex of the baby whether through killing the female spermatozoa, or any other way in order to have a male?
If it is done through having a certain type of food, taking a certain type of medication, or organizing the time of the marital relation, then it is permissible.
Is it permissible for my brother, whom I had suckled, to conclude a marriage contract between his daughter and my son?
Such marriage is impermissible since one`s nephew in this situation is considered an uncle to one`s daughter; consequently, he is the brother of her father by suckling. In such cases, the people in question should go to court to prove the suckling.
Is a menstruating woman obliged to pray during menses, and should she make up missed prayers?
All perfect praise be to Allah, The Lord of The Worlds A menstruating woman is prohibited from prayer during her menses, and she isn`t obliged to make up missed prayers. And Allah Knows Best.