Do the inheritance rules only apply to a society where women don't work, as it seems unfair in today's world where both men and women work to give more to the sons than to the daughters?
The Qur'an says: "Allah prescribes for your children: for a male is equal the portion of two female" (4:11). Since the husband is obliged to spend for the maintenance of the family, his share of inheritance amounts double of that of the woman. The Qur'an also seems to indicate that such a rule is not subject to change in relation to the wife's job by saying: "These are the limits set by Allah" (4:13). A woman can decide if she wants to work, and if she does, she can spend all of her money for herself without sharing it with her husband because of the obligation of the maintenance. The husband, however, cannot abandon his duty to provide for his family. Therefore it is not unreasonable that sons receive more inheritance than daughters. Obviously a good and pious family is bound also by mutual understanding, love and cooperation, and it is up to the husband and wife to reach agreements and divide their financial support and daily tasks according to their situation.
With prayers for your success.