Is the remaining zakat money after my aunt's death considered an inheritance?

Firstly, it is permissible to give zakat to a sick person to cover their treatment expenses if they cannot afford them.

Secondly, if the muzakki (zakat payer) gives their zakat to someone they believe to be poor, but it turns out they are wealthy, the muzakki's obligation is fulfilled, and the zakat is valid. They are not to reclaim it, as the apparent state at the time of payment is what matters. The same applies to other categories of recipients.

Thirdly, it is not permissible for a needy person to take more than their need from zakat if they know it is zakat, based on the hadith: "There is no share in it for the rich nor for the strong, able-bodied worker," and "Charity is not permissible for the rich, nor for one who is strong and able-bodied." If zakat was given to someone who was not entitled to it due to the payer's ignorance, the recipient must return it. If a needy person takes more zakat than their need, and it reaches the nisab (minimum threshold) and a hawl (full lunar year) passes, zakat becomes obligatory on it.

Fourthly, if the paternal aunt passed away and the money exceeding her needs remained with her daughters, and they know that she took what she was not entitled to or more than her need from zakat, it is safer to dispose of it by giving it to the poor and needy. However, if it was included in the inheritance and distributed, there is no blame upon them. If the mother did not know that the money was from zakat, or she took only what she needed, then what remained of it is considered an inheritance for her heirs.