Yeah, I think he should let it go. Talking from personal experience, it wont be easy... But IT will make him feel 1000x better!!!
One thing I'm glad about is that, judging from their reactions( Dillu dropping glass and Mala's statement "kya kardiye hum?") When he said that maybe he should've been dead or that they should've killed him, etc ... AT LEAST his parents REALIZED the 15 years of pain and mental anguish they put him through.
apart from Rudra forgiving and letting go... I think his parents owe HIM am apology too. While it won't make everything all lovey dovey again... It'll be a big step forward in Rudra's healing process.