As the title said
It was when a boy was talking to someone(I don’t know if it was a robot or an alien)
And that someone had told the child
You can only spend one day with your mother
And then a scene where he plays with his mum as if he’s reliving his childhood.
Probably fabrication of his memories but it’s real enough.
That is all I remember. I’m just sad that I remembered the feeling but unable to remember the name.
The part about spending one day with his mother kind of sounds like the ending to A.I. Artificial Intelligence(2001) The boy is a robot who seems to have emotions. After being rejected by his adopters, he goes on the search for the blue fairy so he can become a real boy, which leads up to the boy choosing to spend 1 day with his mother before they all go to “sleep” together.
Hope this helps ^.^