This scene doesn't really fit with everything we come to know of Thanos or Moondragon's childhood. Considering it shows Moondragon playing with Thanos and his brothers after Mentor's people accidentally killed her parents while later stories have an adult Thanos killing Moondragon's parents.
And I assume one of those kids playing around Thanos is Starfox. Who is the third brother?
Is it possible Sui San was Thanos's mother but Kazantra was Eros's? (or the other way around)
What ever happened to her is anyone's guess. She has basically been forgotten and seemingly written out of continuity since her appearance conflicts with the widely more accepted history of Moondragon's family being killed by Thanos.