First, about what you said in the afterword, I don't think you need to flesh this out more.
Can't talk about the prose quality or the words choices you used because I can't speak your language (I used an AI translator).
What I can say is:
Rationally the character knows their loved one is dead but still can't let go. There's survivor guilt added here, too.
I'm guessing that's why the other character looks like that.
Loss is a very personal thing, I think this was just right in terms of what you're showing the reader.
If you extended more it could have broken that sentiment, keeping it more vague was the right decision here since it's a short story.