Is it permissible to swear by (Allah "The Living")?
Yes, it is permissible because "The Living" is one of Allah`s Attributes.
Is it permissible for someone who has forgotten to mention the supplication pertaining to answering the call of nature to say it while in the toilet?
It is disliked for a Muslim to mention Allah while in the toilet, but he/she may recall the supplication in his/her head without uttering it; that is in case he/she had forgotten mentioning it before entering the toilet.
Is the Woman wearing an Islamic veil permitted to uncover the veil in front of her brother in law, husband of paternal uncle`s daughter and husband of sister in law?
Praise be to Allah the Lord of the Worlds. May His peace and blessings be upon our Prophet Mohammad and upon all his family and companions.
The punishment for Zina (Adultery and extramarital relations) is the same for men and women: 100 lashes for the unmarried to be witnessed by a group of the believers. Definitely, this person has incurred the wrath of Allah; however, he must make repentance immediately, refrain from this grave sin, and seek Allah`s forgiveness. And Allah The Almighty Knows Best.
During Ramadan, a man had sexual intercourse with his wife. What is the expiation for that? And is he permitted to pay the expiation?
If a man has intercourse with his wife during the daytime in Ramadan, he must make up for that day and offer expiation. The expiation is fasting for two consecutive months. If he is unable to do so, he must feed sixty needy people. And Allah Knows Best.