He's a kind of cartoonish villain, so you are supposed to hate him and his daughter. That's one thing I don't like about this show. I don't think the writer invested enough in creating real characters. Very often Grandpa and Ms. No especially come across as cartoonish, and back in the early episodes, sometimes it seemed the whole thing was a cartoon. Mr. Baker and Hee seem the most real to me.

If Grandpa were a real character and had really built his empire from scratch, of course he would be attached to it, but he also would be looking for someone with his own kind of qualities to take over. He wouldn't want a successor who just blindly obeyed him. And he would value his grandson's efforts to start his own business, even if he regretted him leaving the family business. But Grandpa No is one-dimensional. All his character ever does is try to control the rest of the family for whatever goal best serves Haesung. He may be a business genius, but he's a zero as a human being. Why everyone kowtows to him is really beyond me. It's just another cartoonish aspect of the story.