Technically, the batkidd have one other brother. Hell, he also saw his father die, and he wore the Robin suit for like a hot second before dying. He caused so much trouble for both Bruce and Dick but did his last sacrifice in a bid to prove that he's not all bad. Granted, like Dick, due to ages at the time, you can say he was more brother-son.

The kid got kicked out of Reform school and Military Academy and a slick liar, even orchestrated a fake hostage situation to see if Bruce cared for him enough to pay the ransom.

And in the notes of the wiki, under rumours, it says he might've been the pre-Jason Todd or pre-Damian Wayne.