I am so sorry to hear about your mother, but although it will be very painful to ask, pull out those old photo's and when your mother is feeling ok that day, ask her to name each person, the year and place. There are special pens and pencils at a craft store you will need to write info on the back of pictures.
Sometimes these pictures are comforting and I can't tell you how many unnamed pictures I have that no one knows who they can be. From pictures comes good memories.
If you feel ok, record her talking, otherwise you will know what to do. My Blessings to you both.