I personally feel it was very insensitive on Sonu Nigams part to share the dialog with Amir about Amir's dad's profession. Amir has taken him in confidence to share it.Why bring it out in open and make Amir catch the spotlight? Had Amir wanted this information shared , he would have mentioend it beofre itself.
It was just not required. Sonu could have said the rest without mentioning Amir's name there.