Remember: War of the Son - The main character's father has Alzheimer's and the main character starts to develop it later on as well, slowly forgetting everyone.
Miracle in Cell No. 7 (Movie) - Main character is a mentally impaired father with the intellect of a six-year-old, who lives in a run-down house along with his daughter of the same age, Ye Seung. But one day he gets framed for something he didn't do and ends up in prison.
Project S The Series: Skate Our Souls (2017) - (I haven't seen this one yet but it sound quite good/ I've got it on my plan to watch list.) Boo has been suffering from depression for a long time, which resulted in self-harm. Moreover, he doesn't eat or sleeps well. One day, he decides to commit suicide, but his plan was thwarted by a group of skaters, led by Simon and Fern, who influenced him to join their group of friends. Can Boo overcome depression and all his fears?