In regards to Pinocchio: >! The grandfather doesn't have dementia, in the first episode Ha Myung explains that the doctor says grandfather's memories are distorted to think that Dal Po is still alive and everytime grandfather remembers that Dal Po is dead, he faints due to the shock of it. Later in the drama when grandfather takes Dal Po shopping and for a hair cut (where the bus scene happens when Ha Myung finds out grandfather knows he isn't Dal Po), grandfather explains that with time his memories became clear and he realized Dal Po was dead.

Grandfather didn't tell Ha Myung this sooner because he loved him so much, he didn't want Ha Myung to leave him. !<