Normally i have mix feelings about emotionless, cold or deadpan type of characters (theres a dere label for these arc type but i cnt rem that term lol) sometimes i do enjoy them expecially if they have a "gap moe" like on the outside they're all emo and gloom but inside their minds is just whacky nonsense lol but in this series case, i think our mc being expressionless , cold or even distant is on theme. He's not the way he is because his parents dont understand him or whatever. he lost his entire family, friends and he's technically in his 50s, he's depressed and suicidal so i cant blame him for not being able to crack a smile. So hopefully if the author plays their card right (by yanno, depending if written well) having the mc to smile, laugh or just enjoy live and looking forward to the future would be worth the wait. So i hope their able to carry such a heavy topic well.
Little spoiler from someone who is reading the novel: the whole point of the novel/manhwa is MC struggling with PTSD and depression, but ML slowly brings light to his life and gradually makes MC show emotions and some life. Not immediately, of course. The process is slow and heartbreaking, but heartwarming at the same time.

I like the story, but i really don't like emotionless and cold people, i hope he will change soon, I mean I know why Is he like this and Is pretty normal to be like this after all that, but it make me sad honestly, I feel sorry for him