Does the Yugoslav Attack refute the Sicilian Dragon? I saw, some weeks ago, a video of the great GM Roman Dzindzichashvili, claiming that Sicilian Dragon is somewhat refuted, or at least it is a dubious system. I normally play the Grand Prix against the Sicilian, but if what I saw on the video is true, I may switch to the Yugoslav attack. 

Basically my question is the dragon really a bad opening and is the Yugoslav attack the its "refutation" (strong word I know) ?
No, it is not refuted, and it is not any more dubious than dozens of other mainstream openings. It's dangerous for both sides, of course. I would not worry about its theoretical status until your rating gets to 2600 or so.

Note also that if you stop playing the Grand Prix, you're going to have to decide what to do against all the other Black Open Sicilian defense besides the Dragon.