You said it.
I noticed it too.
Dev doesn't want to hurt his mother. He actually has every right to question her why was she so unaware of all that happened. But he didn't.
Shaurya himself kept ignoring mother's warnings yet still blamed only her!
It is a case of having less and having too much as much as it is a case of upbringing.
Shaurya has everything and both parents. He had nothing missing. He has too much and too easily. No difficulty in life. This is why he doesn't value anyone or anything.
Mother is protective shield in this show. Dev is united with his shield and honours it. Shaurya is distanced from it and trashed it. He took step towards downfall by leaving Sakshi's hand.
Suchitra checked Dev even at speaking loudly to younger brother. Whereas Sakshi kept laughing off or putting aside whatever Shaurya did. Even a dead Arnab was inspiration to Dev whereas Rajnath was a shame in name of alive father.
In many ways one's child in this show has been a mirror of one's karma too. Sakshi and Raj deserved Shaurya only.