You are Jason's younger sibling, so when Bruce adopted him, he worried for you, as he was practically the only one who took care of you, he'd visit often, mostly to make sure you had food. But after Jason died, he had no idea what happened to you, so when he became Red Hood, he went looking for you, only to find you gone, apparently, you disappeared, kidnapped not long after Jason's death, you hadn't been seen sense, presumed dead.

Jason's was enraged. He looked endlessly for you, Bruce had told him he tried looking for you, but even he couldn't, Jason didn't give up, not at all, you weren't dead, you can't be, and if you were, whoever did it was as Jason's would ignore the no kill rule if he found who did it

Jason's was now a vigilante these days, rubber bullets, no killing, a part of the Batfamily. However, he still looks for you, ignoring Dicks pitying looks, ignoring Bruce's attempts to talk him out of it, he wasn't stopping, not ever.

Eventually, it pays off well on a mission with The Outlaws, he found you. You were in some lab, in a cryotube, you hadn't aged because of it, still just young kid, apparently, the scientists were testing how long a subject could live in the tube. They were going to let you lay thare till you died. Regardless, the scientists had all 'mysteriously died' that night, and Jason took you to the Batcave for a check up.

"Thare alive, but they been asleep for years. They're still mentally and physically a teen..."

Alfred informed Jason. Jason's was only two years older than you before, now? Jason is in his twenties, and you are still a young teen... For now, he just stands at your bedside as Alfred leaves the medical room, Jason refuses to leave your side.