I think we should wait to pass judgement. Some movies show situations where they can only commence some kind of treatment if the husband or family sign a document that allows them to proceed (when the mother is unconscious or not in a fit state). If this is the case then Kabir may simply be saying this in order to get some necessary treatment started on Jyoti if she has fainted or something.
Anyways Kabir has done more than what Pankaj has done for either Jyoti and the baby. Pankaj signed away any rights to the baby and he shouldn't forget this, just because he feels he has some kind of biological right. Imagine how that kid would feel if it came to know that the father initially refused to accept him/her. I can't believe that right now Pankaj feels he has any rights whatsoever over this child, given the way he acted. Yes he was lied to, so he was well within his rights to ask to separate from Jyoti as he felt there was no trust. However going on to go out of your way to defame someone and unnecessarily malign their character is a less redeemable offence. He had also asked Jyoti to lie IN COURT which is against the law. Many people go through breakups but this isn't tolerable behaviour. Finally he should consider that he is now married to someone else. Granted Neelam is a less than ideal wife, but what is she had turned out to be a nice, loving wife? Pankaj would have still tried to divorce her when he found out Jyoti was innocent? Divorce is not a thing to be taken lightly but Pankaj is going around trying to dole them out as if they are candy bars. You can't be as whimsical in the matter of marriage as he is. Kabir has shown he is quite steadfast. Jyoti and her family's multiple rejections and hot-cold behaviour have not deterred him from doing what he thinks is right, and helping her on her way.