Sujata- dont forget that they showed that Khushi;'s dad was or is a Police Officer . He may be missing in action or may be in a coma or may be kidannped by terrorists etc and may make a magical comeback when they decide about adoption, leaving AshNi longing to have a child ... Nahi to Khushi track ka kya purpose hai , yeh clear nahi hoga..
Khushi track ka purpose is to bring an orphan into their lives...just as Ashutosh came into Baba's life...we all know the longing for the child is not likely to happen...unless circumstances have changed dramatically...
About the father, that may well happen...but not so soon..of course, we have no clue if he is alive...but if he is, then he will probably return later...because the scope for drama will be greater then...now, it will be a convenient cop-out...but if they want to close the track abruptly, like they did with Mallika, then it could still happen!