Is Zakat due on the security deposit for an apartment held by the landlord, and is it permissible to give Zakat to an aunt if the grandmother lives with her?

Zakat must be paid on a sponsorship. It is permissible to give zakat to one's paternal aunt if she is among the eight categories. As for the grandmother, it is not permissible to give her zakat due to poverty; rather, one must spend on her from one's own wealth since she is among the ascendants.