Curate, connect, and discover
A DCXDP rewrite of Ric Grayson that keeps absolutely nothing besides the amnesia.
Danny and friends find an injured Nightwing and take him in. At first they thought this might be a good opportunity to prove to the justice league that ghosts can be kind. "See, a ghost gave you medical care! Now please stop hunting us." But when he wakes up he has no memory... so they lie.
They tell Nightwing, who is apparently Richard Grayson(!?), that he is Danny's brother who is estranged from their parents. The idea is simple, "Ric" will see that ghosts are people and how bad the GIW make life in Amity, and when he gets his memory back he can report this to the justice league. (The assumption being that the league knows and just doesn't care, so they need to trick a league member into caring.)
There are a few (a lot) of problems with this plan though. For one, it is a lot of work keeping Ric away from their parents who would spoil the lie. Hiding the fact he is a hero from Ric is also hard because even if he doesn't remember being Nightwing he still has instincts to get involved every time something happens
And lastly, Ric takes being a brother to Danny and Jazz very seriously. As a mater of fact, he refuses to drop it even when he gets his memory back. If Danny didn't want a new brother he shouldn't have lied.
The bats have been scrambling to find Dick this whole time, but with the information blackout in Amity and ghost tech interference, it takes a while. And, no the bats are not happy when they realize that Nightwing has been kidnapped and was basically forced to play house. But Dick is very protective of his new siblings and defends their choices. They didn't have any good options! Besides Dick kind of sees this whole thing as a weird vacation.