The dad aged.
It's summer season and she's still wearing winter uniform.
In summer season they have that commemorative day when the dead go back with the alive.
Still, the author said the ending was inconclusive. So keep your minds opened.
@germ4Nn
but the uniform the girl is wearing in the recording isn't hers, since she was still in primary school at the time of recording and her dad wanted to see her in a middle school uniform. Anyway I'm trying to interpret positively
The daughter is gone... the end is another kid saying "dad, I'm home!" And when he heard that he thought of his daughter in her uniform from the video that he just watched. I'm literally crying rn :/