What is the ruling on my action of taking a sum of money from my deceased father's estate in Saudi Arabia to compensate for part of my inheritance share, after I initially relinquished it to my non-Muslim mother, who took possession of the entire inheritance in Britain according to local law, especially given my difficult financial situation and the fact that my elder and younger sisters are still relinquishing their shares? And must the remaining amount in Saudi Arabia be divided according to Islamic Sharia? And what is the ruling on my younger sister residing with my elder sister and her husband without a mahram?

If you relinquished your inheritance on the condition of financial hardship and your sister completing her education, and neither of these conditions was met, then you are permitted to revoke your relinquishment. If your mother prevented you from receiving your share of the inheritance money in Britain and seized it, then you are permitted to take from her wealth an amount equal to your right (the issue of al-Zafar). As for the money your father left in Saudi Arabia, you have your legitimate share of it, and it must be distributed among the heirs according to the legal division. Nothing from it may be taken except with their consent. Your two sisters' relinquishment to your mother does not transfer ownership to your mother until it is taken possession of. We advise you, if you are able to manage your affairs, to leave your share or part of it to your mother as an act of filial piety, even if she prefers your brother over you. As for your younger sister, it is better for her to reside with you for protection, and she must obey you as her guardian. You can seek mediation from someone to reconcile between you. It is not permissible for her to reside in a house where unlawful acts, such as being alone with a non-mahram, may occur.