All perfect 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.

Islam urges Muslims to maintain ties of kinship to enhance love and mercy. Allah The Almighty Says (What means): "Blood-relations among each other have closer personal ties, in the Decree of God." [Al-Ahzab/6]. The Prophet (PBUH) said that maintaining ties of kinship is a sign of perfect belief. Where he (PBUH) said: "Messenger of Allah (Blessings and peace be upon him) said: "He who believes in Allah and the Last Day, let him be hospitable to his guest; and he who believes in Allah and the Last Day, let him maintain good the ties of blood relationship." [Bukhari].

Members of the Muslim family cooperate with each other in all that is good and the big brother is like a father to his younger brothers and sisters. He helps his parents in taking care of them and raising them properly. Similarly, the big sister is like a mother to her younger brothers and sisters and plays a similar role. For this, they have the right to be respected and appreciated. Commenting on the Hadith (The right of the big brother over his younger brothers and sisters is like the right of the father over them), Al-Minawi (May Allah have mercy on him) said: "It means that they are obliged to show him respect, reverence, and not to differ with him." Besides, Al-Hafid Al-Iraqi said: "Its Sanad is weak and was narrated in this same form by Al-Hakim and Al-Dulaimi." [Faid Al-Khadeer, vol.3/pp.394]. 

However, a brother`s guardianship over his rational adult sister is only restricted to concluding her marriage contract. In addition, generosity dictates that a brother takes care of his sister and treats her with kindness. Thus, he it is forbidden to abuse her in any form, take advantage of being her brother, not allow her to do things that are lawful, or beat her up since these acts cause severance of kinship ties and lead to spreading mischief in the land. Almighty Allah Says (What means): "Then, is it to be expected of you, if ye were put in authority, that ye will do mischief in the land, and break your ties of kith and kin?" [Mohammad/22]. However, if she committed any violation of the teachings of Sharia, then he has to advise her kindly and she has to obey him in what is lawful. Moreover, such conflicts are usually solved with mutual understanding, compromising, and seeking the intercession of the people of wisdom in the suitable time. The Prophet (PBUH) said: "He is not one of us who does not have mercy upon our young, respect our elders, and command good and forbid evil." [Tirmithi]. And Allah Knows Best.