A man taking the money of his sister and abstaining from supporting her

Q: My maternal aunt is around 90 years old. She owns land, real estate, and other property that she inherited from her husband. However, due to her old age, she is unable to manage her wealth and her brother and her stepsons, from her deceased husband, have been embezzling her wealth. Her brother, who was taking care of her, was taking from her money for the last 15 years before he finally forced her out of her own home. When this happened, she came to live with my mother who does not own any property and depends on me to support her. My aunt's brother has been cheating my aunt, and the little money he does give her does not even suffice to cover the cost of her medicine. Thus, I am obliged to provide for her as well as for my mother. Her brother and stepsons have even taken the flat that she used to live in against her will. After family negotiations that continued for five years, I have not been able to convince them to increase the meager monthly stipend they give her, which is not even sufficient to feed her. During these last five years while she has been living with my mother, I have been spending on her after her brother refused to let her live with him and at the same time he refused to increase her monthly stipend, which is taken from her own money. We tried to convince them (Part No. 25; Page No. 360) to sell some of her farmlands to provide for her needs, but because of her senility and lack of experience in such matters, she is unable to make sound decisions and refused to sell the property. To compound the problem, some of her brothers have refused to sell any of her property to cover her expenses, while others agree. In this case, we cannot sell any of her property as it would cause a split in the family in addition to the fact that my aunt, the owner of the property, is unwilling to sell anything as a result of her inability to judge what is in her best interest. In my current state, I can no longer afford the cost for her food, clothes, and medicine, as I can barely afford the needs of my mother, my poor brother, my wife, and children. My aunt has no children; she lives in Egypt, all her properties are in Egypt, and all the people concerned are Egyptian.My question is: Can I count the money that I spent on her as part of my obligatory Zakah? Bear in mind that although she is wealthier than me, her property is not at her disposal since her brother took it without her permission. Also, the money I pay in Zakah would be sufficient to provide for her needs. Or am I obliged to spend on her according to Islamic law, in which case the money I spend on her is not to be considered Zakah? It is worthy to note that I may not inherit from her if my mother dies before her, and my mother's health is getting worse day by day. Give us your advice; may Allah reward you the best reward.