You were Grisha's other kid, right now Eren was trying to re-esemble the yeager family so he went on a quest to find Zeke and Grisha and now you, they all went through his memories and finally found you, they were in a crowd right now and saw you, Grisha was so happy, Zeke was excited and Eren was generally happy to bring the hole family back together

Grisha: gasps Zeke: I cant believe it Eren: Lets go talk to them