Communicating via one's sister before marriage

Q: A girl is engaged to a guy, her nikaah will be after few months. The guy's sister is close friend of the girl. So is there anything wrong if the girl asks her friend who is the guy's sister to convey him some deeni demands that she has from her future husband? (like the girl wants her husband to get involved in work of tableegh and wear Islamic dresses and few other demands). Similarly, is there anything wrong if she put forth these demands to her future husband via his sister?

Inheritance

Q: I want to know the ratio of distribution of shares to the heirs of the deceased. The details of heirs are as follows:

1-widow

4-daughters

Living with a brother who is one drugs

Q: I'm living in my parents house with my brother who is on drugs. He keeps on stealing my stuff even after I speak so nicely with him. This is going on for years. He frustrated me and my wife and my wife is really putting pressure on me because of it. She even threatens to divorce me. I do confront him in a respectable way. Will it be the right thing to fight and hit him? My wife says I'm too soft and probably wants me to bash him. Will hitting him do justice according Islam? Please advise me.