Is it permissible for the big brother to force his sisters to wear Hijjab (Islamic wear) if their father didn`t do his part in this regard ?
All Perfect Praise is due to Allah, The Lord of The Worlds
The father`s attention should be drawn gently and politely, and the sisters should also be reminded with good words since Allah, The Almighty, Says (What means): "O ye who believe! Save yourselves and your families from a Fire whose fuel is Men and Stones." [Al-Tahreem/6]. And Allah Knows Best.
What is permissible for the person who wants to ask for a woman`s hand in marriage to see from her body?
He is permitted to see her hands and face only, but if he wants to see more, then he has to send a woman that he trusts to do so.
If husband doesn`t pray, but wife does, is their marriage contract considered valid or not?
All perfect praise be to Allah the Lord of the Worlds. May Allah`s peace and blessings be upon our Prophet Mohammad and upon all his family and companions.
Not observing daily prayers is a grave sin, but doesn`t invalidate a person`s marriage contract. However, we advise you to save your husband from hellfire by convincing him to observe the prescribed prayers. And Allah The Almighty Knows Best.
I want to buy a house by having a loan from a bank?
If taking a loan from usrious banks it is impermissible; on the other hand, if this took place through Islamic ones then it is permissible to get the loan, since Allah the Most Exalted Said (What means): "And Allah has made buying lawful and forbidden usury (riba)." And Allah Knows Best.