The alternative reading to the events so far is that Eunyung is right this time. He was wrong in the case of the uncle, and the way these things go in comics is that the first time throws readers off so they'll be surprised again the second time.
If we think about it, the situations are diametrically opposite. There were reasons to be distrustful of the uncle, and now everything seems to point to the dad being nice. Doesn't it stand to reason that just like last time the big reveal was that the uncle was good, this time it will be that the dad isn't?
If I were to squint long and hard at the chapter, I'd say that the dad wasn't very nice reminiscing about a bad memory involving the mother right away the moment he meets Haejoon for lunch. Even if he was disappointed in her, she's dead and he ought to be tactful around the son she raised.
My particular bet is that he isn't bad, or after Haejoon's money, or anything dramatic like Eunyung's suggesting, but it will turn out that he and Haejoon will have differences in views and opinions and won't get along in the end. Then again, I may be wrong, and the fact that Haejoon's asked his uncle whether there's something he wants to tell him may be what settles the issue come next chapter.