In real life someone is Shaurya's position would never be able to forget his parents and it's not even needed..
Shaan literally started treating Anokhi as a daughter since the time Astha told she is like her daughter and ignored Shaurya for years because Astha left him..
This had to hurt!! It was easy to replace their child. And both have this attitude that they deserve forgiveness as if they’ve done anything besides create Shaurya and give 4 years of rearing.