Khums is not our money like what we give in charity, but it is the money of others which must be given back by us to them. Half of Khums is called Sahm e Sadat and the other half is called Sahm e Imam (AS).
If your aunt is a poor Sayyed, many of our Marja’s say that poor Sayyeda can be given from the share of Sadat from Khums ; Sahm e Sadat.
If your aunt is not Sayyed, you need to seek permission from the Marja’ of Taqleed. You can easily contact the Marja’ via email or his office website.