That undiluted happiness on Devavrat's face upon beholding Ganga was heartwarming. Their last meeting wasn't pleasant and Devavrat had departed saying that now Ganga will have to come to her son because he won't return to her.
That's what Jahnvi did. 
This scene is inarguably the best scene of this mother-son duo and its essence is unique to them alone. I think even Mukesh Khanna will agree because he himself described it as marmik I.e. poignant.
It warms one's heart when one beholds the joy on the aged son's face and breaks it the moment the goddess lowers her hand in reluctance and expresses an agonized confusion over the fact that her Ayushmaan Bhava is no more needed by Bhishma who desires a release and requests a blessing pertaining to that.
Filled with effortless poignancy and pathos, Bhishma-Ganga scenes are in fact one of the best creative liberties taken by this show.
Kumkum Bhagya
Anupamaa
