I don't know what the standard term is for AGD AIs (maybe Taualumna can elaborate), but I wouldn't be surprised if our terms "sister-mother/sister-daughter" applied to our AIs too.

I remember at the Atlanta Convention in 2001, there were two AIs with lovely "sister-mom" stories.

One was a mother of two Alpha Gams. Her two daughters both served as her sister-mom.

The other one was a pledge back in the 60s or 70s I believe, but she had to depledge for personal reasons. She came back to AGD as a Convention initiate, and her original sister-mom from her college days stood by her and gave her her Badge at Initiation.