LWJ's morality never changed..
I have seen a lot of ppl in fandom , who have seen cee queee elll no doubt, think that w*ngxian is a dynamic where perfect protagonist WWX finds love and LWJ the love interest gets influenced by WWX's free spirited ways. He finds unconventional morality and justice away from the orthodox clan of his and becomes open and what not...yeah no.
That is a show only invention which hardly makes any sense. After all there is no thing called "just" POW treatment in this fantasy. WWX won the war and basically forgot about the Wens and what would happen to them beside being homeless and in custody of Jins. They just inserted that for sake of sprucing up their main character to adhere with certain standards censors of the country demands
In the book, WWX is the kind of person who is raised with the idea that his life is not his, its OTHER'S. Other people who have done him favors by taking care of his needs, so he should repay it with his life.
At first it on surface doesn't bother him because he is boundless and talented and hence has a lot to give to others. Especially his clan, the Jiangs, who raised him. He has even convinced himself that he doesn't even like marriage!So what if it kills him on the inside and he is now a functional alcoholic at 15? he can just laught it off and pretend he thinks marriage is jail anyway! its nothing but chains! ( note the word "chains" when he says to Yanli, coincidentally what his life is like with Jiangs. Chained by obligation to restore an elusive happiness they lost because Madam Yu, the toxic matriarch cannot accept accountability)
Wens are just another obligation in long list of obligations that he HAS TO repay for saving JC's life and keeping it a secret from him till their literal dying day. Wen Ning blabbing doesn't count because he is not technically alive. He rescued the Wens because Wenqing knew he would repay her if she approached him . WHICH HE DID.
Unfortunately WWX's ability got outscaled by sheer adversity and bad karma he was facing thanks to situation beyond his limits. His powers alone cannot face off against the cultivation world which ironically happened partly because of the same powers which became out of his control. That is where bad karma is. He created a power where he could exploit the souls of dead and there is only so far it would take him.
In the end WWX's life fell apart because he has to keep paying obligations to others especially Jiangs without getting anything in back. WWX is expected to do everything in his power to mollycoddle JC, to keep Jiangs safe, but do Jiangs feel obligated to back him up if he decides to keep Wen remnants safe? Nope. ( coincidentally, WWX and shouldn't have to even ask, he is the head disciple and JC remembers the Wen siblings AT LEAST sheltering him and his brother during times of crisis...JC truly is a taker from so many people and he never gives back). He has never known a life where people have his back before the Wens and LWJ.
This is why he lowkey admires the Lans. He wanted to replicated by Twin Jades with JC. How tragic is that??
WWX is the one who wants to be like Lans. He for the first time didn't say some stray individuals but a whole SECT backing EVERY member it has no matter how close they are to the Sect leader or not or have clan relationships or not. He saw them punish LWJ for injuring his own elders who might not have been his clan members. He saw them punish LWJ despite being son of the sect leader...something he NEVER saw happen in his own clan where the way he is treated by everyone and how JC is day and night different! He saw for the first time what is its like how to live in a place where everyone is treated equally however cumbersome its rules are. They truly mean their morals and their rules.
Its LWJ who was going around helping poorer, random people in need of rescue or help even before WWX 's first life. It was LQR who warned him to not dable in Gu Dao its against morals of a cultivator to exploit the dead. Its LXC who sheltered him and LWJ when it would have been convenient to throw WWX out to save his brother instead ( something WWX is familiar with , that is how it basically was, leaving the Jiangs) . WWX is the one who wants to keep up with LWJ and now helps random people around too, when he didn't use to before in his first life. That detail in the extras is important- Not because WWX lacked morals but but because there was even a higher standard set by LWJ that he admired and now helps his husband with.
So if WWX is the one who is influenced by morals of LWJ and not other way around...what exactly LWJ's character growth change? Its the fact that he opened up his heart to love and decided its not a bad thing to follow the path of his own father.
Imagine being LWJ, being born a prodigy to a clan leader, who is basically looked down as a wasted potential because he chained himself to his criminal mother. LWJ loves his mother but he cannot deny what she did was wrong. LWJ was raised by his uncle who had to basically handle everything in his sect and basically raise the brothers too, when as second born, he probably had more freedom to do as he pleased and be free of obligation to have any heir. All snatched away in a second when his elder brother decided that its worth it all to keep his love/wife alive no matter what heinous action she committed against their sect. The PRESSURE on LWJ to not repeat the mistakes his father made and be on right path but also with right people must have been immense.
LWJ beside later thinking WWX is straight and he has no chance, also thought that WWX is that he is not right person he could share his ambition with of being a righteous cultivator either- a kid who is laughing about the idea of harnessing the resentment of dead, gullible, hapless souls like they are just inhumane products rather than a another pathway of living being who also need level headed compassion or attack depending on threat to be delivered from cycle of reincarnation , is frankly NOT morally sound. But as he knows him he realized WWX is not bad, he is just misguided ( like most of the cultivation world is. More concerned about powers and treasure and not what Cultivation as a philosophy even means...now wonder there is only ONE Boashan Sanren) and as tragedy slowly unfolds, LWJ realizes his decision to keep his distance from WWX has cost him any right to keep him safe.
This is why he was willing to take WWX to Gusu and follow the path of his father and mother. Something he never wanted to do but is willing to just to keep WWX safe. Exactly like his dad. And he FOLLOWS THROUGH with it when given second chance when WWX comes back from dead!
In that sense LWJ and WWX have that parallel- both are expected to shoulder the burden of not repeating the "mistakes" their parents made and not make their current family unhappy. Both realize that they didn't make a mistake as people think and avoid being a tragic ending.