Spoilerrrr....
So uhm, the mother is sick, i think the box that the uncle saw before in her messy room was her medicine? Not sure hehe. Base on my understanding(raws) I think the mother will live with the uncle with her remaining years without getting married. I think the FL gave up her feelings and run away from home? So when her mother died she came back to the uncle. Yeah im not really satisfied with the ending. I really hate the existence of her mother honestly.
"you have nothing going on in that brain of yours" i guess he got it from his mother?