Should the sister remain with the family?

Hello,

Here I’m with another one of those questions.

Just watched a drama… I need opinions on the outcome.

So, we have a couple…A and B. They have a 17 years old daughter (D) in high school. She was extremely talented and was aiming to be a scientist.

Life goes on and D has some trouble in school but she doesn’t share what it was.

Soon B is expecting a second child and she goes to hospital for delivery with A and successfully delivers a baby boy(SB) , at the same time unknown to the parents D commits suicide.

The news devistates the family, A goes into depression with alcoholism and started shutting himself inside D’s room, but B manages to break him out after a very long time. B was hurting inside, but she didn’t show it.

The family doesn’t celebrate SB’s birthdays due to the very same reason.

Life goes on.. And 17 years goes by.

Family still doesn’t celebrate SB’s birthday but this time he was given a gift by his parents.

The gift was the key to D’s room, which was now his.

He was happy… He unlocks the door and sleeps on the bed.
When he wakes up in the morning… He sees D.

So long story short, somehow he’s able to see his sister’s ghost, she tells him she’s been trapped in the room for many years.

He asks her why she had to die on his birthday..?
She tells him she doesn’t remember..

He tells her that he will help her remember, maybe that’s why she’s unable to move on.

So after everything is resolved…
D has the option to either stay with family or move on.

Sister wants to stay with the family… But only SB can see her.

SB wants her to move on for rebirth.

I know it’s silly but what should be done here?

I’m sorry if the question is too long.
I cut down quite a bit from the story to keep it as short as possible.

I appreciate the answers as always.

Regards