Where the heck is shen yu in the second story? Did he died or what?

Nah, he didn't die. He just doesn't appear anymore for reasons unknown to us readers. Hell, I don't even think the Author knows the reason he's not in the second part It sucks bc I cant see the Emperor and Shen Yu to allow their son to become like this and treat Li Qing the way he did.

The only thing I think is the Author wanted a Part 2, and lost the plot earlier in Part 2, so they basically regurgitated Part 1 into Part 2, but made the ML worse and even more despicable.