Is it obligatory for a brother to provide for his poor sister?

Question:
He says: Honorable Shaykh, may Allah grant you success, is it obligatory for me to provide for my poor sister? And is it permissible for me to give her from the zakah? If she were not an heir, if she died while poor.

Answer:
It is obligatory for you to provide for her. Apply the three conditions that were mentioned to you to the actual situation. Yes, so if they apply to her, the obligation to provide applies; if they do not apply, the obligation to provide does not apply. You have the criteria, yes.