Why does British drama say "Where CAN she have gone now." instead of "Where COULD she have gone now?"

Question

This is from a British drama Late Starter (see:35:44-35:46)

In the film, a man's wife has left without saying where she has gone. So he is looking for her everywhere and visiting her friends' houses thinking she might be there. So in one of her friends houses, he says to the lady of the house:

"Where can she have gone now."

The use of "can have v3" caught my attention. We learned that we would not use "can+have+v3" for speculations. Instead we use may/might/could have done.

I mean we would say "She could/might/may have gone to a friend's house." but we would not say "She can have gone to a friend's house."

But, as you see, the man says "Where can she have gone?" instead of "Where may/might/could she have gone?". So, I want to ask, is this usage correct or is it non-standard English?

Answer 1

It is a valid use of 'can'

See here for a fuller discussion: https://english.stackexchange.com/questions/491794/what-can-have-happened-valid-or-unnatural

The point here is that although 'can' normally indicates 'the ability or permission to do something', the use in 'it can't be true', is to refer to the possibility that something is true (or in that case impossibility), and it is a small step from negative statements where 'cannot' is perfectly standard, to its use in questions.