I agree, now that I think about it, DS9 actually saved him and added some more dimension to his character.
As far TNG was concerned, we never would have seen him again after he abruptly disappeared to live with his grandparents.
The way DS9 suddenly left off with him was awkward though. It seemed like a quick fix with no real follow up.
Trek has always had a thing with the dysfunctional families- almost every main character in each series comes from a family that you could describe as dysfunctional.