If a woman makes a vow to slaughter a sheep, and her husband is the one who buys it for her from his own money, and he says: "It is for you until you fulfill your vow with it," Is this permissible, or must she buy it herself from her own money?

If her husband gave her the sheep as a donation for the puprose of fulfilling the oath she made and was slaughtered by the wife or the husband on her behalf then the vow she made is fulfilled. And Allah Knows Best. 

1- A young man whose father and grandfather are dead. Unfortuntly, he passedaway leaving a mother, two sisters and a brother. Do his paternal uncles inherit him? 2- A man died leaving daughters, a wife, brothers, a mother or no mother. It is well known that the daughters inherit two thirds and the wife one eighth. To whom does the rest of the estate go and what is the evidence on that from the texts of Sharia?

A pious man proposed to me and my father was hesitant in this regard because he is black, am I sinful if I accepted his proposal?

If the suitor is pious, color isn`t a drawback. However, try talking to your father kindly, so that he approves of your marriage with contentment, and that is better for you.

Is a woman`s face an Awrah (a private part) that should be covered?

During prayer, a woman`s whole body is a private part except the hands and the face. Outside the time of prayer, scholars are of the view that a woman should wear on her Islamic attire to avoid temptation.