According to another commenter on another website:
"GUYS. I'm pretty sure the old man has dementia. The first page with his ID picture says "My face" under it. Then it lists his basic information, including his name, address, family relations, etc. The long note says, and forgive me for the bad translation,
"Sim Deokchul
I have dementia.
Everyday I write notes to remember well.
I have to check (? I don't know what it says here)
Fortunately, the symptoms are not severe yet.
It's a slow process.
But do not be alarmed.
Make notes a habit.
????? (Can't read this line)
If I make note here, I can remember some of the things listed here.
I have to go to the hospital."
Etc (I got lazy, but you get the gist of it)"