Actually I like that LFS is not a complete Mr Do-Good-Stand-By-The-Sidelines. That will make him less like masculine than I imagine him to be! While he says that he will only help if needed, he has appeared (ever so instantaneously!) when she needs help and with assistance far exceeding that of pure friendship which even the drama troupe can tell (and that horribly bad actor Tian Sheng can detect) - which friend or pure drama fan gives the troupe the fees for a show not performed so that the theatre owner does not harass them and buys a full chest of makeup that can last them for half a year (including colors that are not really meant for performing and everyday use - kinda like buying a present for TY). I like having Luo Cheng around - he kinda speaks his mind and sets out the blatant truth to what LFS is doing. He would complain that LFS cares more about what is going on in TY’s life compared to HL (when LFS was planning what to do to stop her wedding to TS), remind him that the pursuit of love does not have to be honorable all the time and he doesn’t believe that XJC didn’t cheat in his competition with LFS (which XJC did by changing the time she was supposed to meet LFS and hence giving HL the chance to tell TY about why XJC gave up being a doctor which essentially guilted TY into letting him out of friend-zone - in fact, XJC specifically told LFS never to tell TY that because he knows it would guilt TY but his plan with HL achieved that end game with him still acting blur when TY confronted him with the fact). At least that’s my interpretation-la. I like that when LFS again told TY he likes her (when she came to visit him in HL’s house) and she said she won’t give an answer now he said in a side whisper that “I should have listened to Luo Cheng and just snatched you away by force! Kinda exactly what a triad boss would do! LOL) LFS may like TY a lot (his worried face during her first performance after her father’s death) shows that but he still has his own life - which I think is healthier - anyone who places love as the one and only thing they need to do and be concerned about gets way too obsessive and weird about it - XJC doesn’t really care about his job either as a doctor or a policeman because money comes easy to him even when he is on the outs with his dad. Despite a broken heart, LFS still has to manage the increasing turf fight with the new triad, run the nightclub and spend time with Hong Lan whom he considers his sister.
The way LFS handles the suicide note is cool too - no big theatrics; he read it (when he really shouldn’t have), went to get her back to see her dad - bear in mind that he did think of letting them elope and he only changed his mind when he realized how sick her dad was and only had that day to live because he knows if TY had missed the opportunity to see her father for the last time, similar to him she will never forgive herself. His concern for TY’s personal wellbeing outweighs his need for her being happy with the man she loves (or think she loves in my opinion) because TY says that she can do everything her dad wants except marry her brother since she is already in love with someone else and would rather die than go through the wedding - if her dad was not critically ill, he would have let them go as it seems it is what TY wants. But he made his own decision to bring her back because he knows that while TY wants personal happiness, she couldn’t live knowing that she missed her father for the last time - he knows her well because that’s exactly what he would have done too. In my mind, LFS will not pursue TY until she is over XJC because her actions to date shows that she has chosen XJC and he respects that. TY is not a wishy-washy person toying with both guys’ feelings - she picked one and is being loyal to him although at this point she knows that LFS likes her and she treats him only as someone who has saved her thrice.
Agree with @BreezeC that what TY likes in XJC is the image he presents - a warm hearted, optimistic, idealistic man hence the reaction when he became a policeman - how many first loves are like that; built on a weak foundation but sustained by romantic yearnings. He sees her as a beautiful object that he can show the world to and she puts him on a pedestal as the key to a world she wants to enter. With LFS, I feel it will be more a meeting of equals and a much more mature relationship.