So what's the truth? The truth is that Karan was present on the sets of the film, but in the capacity of a friend, as a good luck charm. Also, all talk of Karan being the second unit director is absolutely false, for the project is SRK and Anubhav Sinha's baby entirely. They have worked very hard on it and it would be unfair to SRK and Sinha both if news like this is taken seriously. In fact, Karan was in his hotel room almost every single day, which wouldn't be the case if he was co-directing the film.
Also, the talk about Karan 'directing' the songs of the film is equally baseless. Sure, Karan is a multi-faceted personality, but not a choreographer. At least not yet!