18 y/o daughter left with no return

So, yesterday, my couple's only child left for a job training seminar thing and she hasn't returned. When is she coming back?

I think she will come back when your family who owns the house at the minute dies - then she will come back and live in the house

I have been in a similar situation when I sent the son junior to Europe on accident when he was 3 at first I thought it was someone else's child I was sending to Europe so when he disappeared to go to Europe I had no idea where he had gone . The kid/adult will come back to start the new generation if you want him / her to.