Is it permissible for a wife`s family to demand her husband to divorce her although she doesn`t want that?
It is forbidden for them to do that in case their daughter doesn`t want divorce unless there was a sin that continues as long as the marriage survives.
Is it permissible for a person to give the Zakah (obligatory charity) to his daughter-in-law?
Yes, it is permissible for a person to give the Zakah to his daughter-in-law if she was poor, and wasn`t provided for sufficiently by whomever is obliged to provide for her. And Allah Knows Best.
Is it permissible for the doctor to uncover the hair of a female patient out of necessity?
It is only permissible for him to do so when there is no female doctor, and he should examine the patient in the presence of one of her Mahrams(unmarriageable kin).
What should a woman who is in a state of menstruation, or confinement do if she became ritually pure during the day of Ramadhaan ?
If she became pure during the day time of Ramadhaan, it is desirable for her to fast the rest of that day, and to make up for it along with the days that she had missed due to menstruation. And Allah Knows Best.