Can someone help explain why the dad is away?

Basically the father super sick and he had to go back for treatment and he was in a coma until now

Basically he had a tumor that made him slowly forget how to function as a human and he didnt want his mom to deal with taking care of him for the rest of her life, do he fled to America hoping that shed move on from her life and forget him

He wasnt in a coma up till now he just couldn't remember anything till a year prior after seeing that drama he loves

Long story short,

Father had a tumor, it made him slowly forget like the top reply, and after he got out of coma, he forgot everything for 40-50 years I think? And afterwards, there was this movie that he was interested in, because of it, made him remember everything about mother again.

So he thought she was alive so he wanted to go back, only to hear that she already passed away. Now that he's on her grave, he regretted doing allat and arrived late.

Dayum tks thats so saddd

Tks!

omg