
Would it be stupid to believe that JK won't automatically assume the worst of Kim Dan? He's shown that his personality is completely flawed, and he's selfish. Excuse my word vomit;
But I think that might be just due to how intensely he hides his weaknesses, Kim Dan being one of them. My prediction is JK has caught feelings for Kim Dan, and is fiercely trying to hide/undo that fact by being a POS(which is unforgivable). Paired with his anger issues and personality, this makes him especially dislikeable and selfish.
Moving on, he's made it clear he sees Kim Dan as one of his people, because of that whole arc, I think it might be possible that he becomes the slightest bit aware and realizes what's actually going on. Maybe even getting defensive on Kim Dan's behalf. Alternatively, this would reveal that Grandma is deteriorating more rapidly, and maybe then he'll have the mind to show some respect and empathy.
This is expecting a lot of JK, who's shown himself to be somewhat of a complete narcissist, I know. But I imagine this author will try to redeem JK to some extent by showcasing some form of loyalty.
I also reckon Grandma's favor will become relevant to their dynamic somehow, and that JK has actually read Kim Dan's letter/card.

I'm intrigued by this manga, but the different translators/uploaders is distracting. The watermarks later are obstructive, the cleaning becomes sloppy and the translation starts making less sense. Even worse, some of the pages are jumbled up. I respect people taking their free time to make this work available to us, but the drop in quality has been disappointing as it can make it hard to follow the story.
For such an ironic work, I'm surprised the uploads aren't of higher quality! I'm thankful the story is here at all, of course, it's just very distracting.