If a woman has wealth...
If a woman has wealth, she is not required to spend it for her family; she may save it if she desires. All possessions that she gains through work, Mihr , gifts, inheritance, or any other legitimate method are solely hers and she can amass it all if she wishes. This is in contrast to men, who are legally and canonically required, in addition to bestowing Mihr , to provide all living expenses of their spouses and all other members of the family.
Thus, women are partners in all the possessions of their husbands, including their husband’s inheritances, which are indirectly given to them; while a woman’s inheritance is absolutely and unquestionably hers only. Because of this, Islam intended to assist men by formulating the laws of inheritance in this manner. With regard to this fact, can one still say that Islam discriminates against women in regard to inheritance?
If you fairly examine the matter, you will affirm that not only have women not been treated in a biased manner, they have been supported. Various Hadith indicate this reason. Imam Ridha (‘a) has declared: عن الرضا (ع) قال: علّة إعطاء النساء نصف ما يُعطي الرجالَ من المیراث؛ لأنّ المرأة إذا تزوّجت أخذت و الرجل یُعطی؛ فلذلک وفّر علی الرجال.
Another reason is that a wife is the dependant of her husband and he must pay for her expenses, but a wife is not required to pay her husband’s expenses or financially support him in need.
Hence, men have a larger share and this is [the interpretation of] the declaration of Allah: Men are the protectors and supervisors of women because of the advantage Allah has given some over others and because they support them from their means [^4] Hisham ibn Salim narrates: هشام بن سالم، قال: إنَّ أبي العوجاء قال للأحول: ما بال المرأة الضعیفة لها سهم واحد و للرجل القوي المؤسر سهمان؟ قال: فذکرت ذلک لأبي عبدالله (ع).