Responses

Park Huitae was Jungman's father-in-law, Jihyung's maternal grandfather (Jungman was dirt poor, his wife was rich).
Huitae had several sons, and the eldest died abroad. Huitae had also one daughter (Yeonju), Jihyung's mother/Jungman's wife. Huitae divided his large business into several smaller ones amongst his living children, one of them was Yeonju. Yeonju died in a car accident and Jungman was blamed for it.
The other family: the niece of Huitae, and her husband.
Pls anyone can correct me, but that's how I understood the chapter.
It's a stupid story, but imho chapters 57 & 58 are interesting -- they explain this whole family & business situation well (family background, who is who, etc) and we are shown why the father & son keep their distance from each other. (I don't believe they genuinely hate each other.)