Seriously, what does the cat think?
If the cat is more attached to your daughter than to anyone else in the family, he/she will probably be happy to move in with her.
If the cat loves you all equally, then she will miss you.
If you have a garden and the cat is used to going out, and your daughter is moving into a flat - don't consider it for a moment.
If cat totally ignores daughter's boyfriend or has made her dislike of him plain then it is a no-go. Likewise if daughter's boyfriend dislikes cat or cats.