No, for sure it was 'Daddy' she was ask for, hana

To be fair I always heard it as 'Danny', like the guy's name is Daniel.

This is common in many parts of the world. Once a couple has children, the mother and father refer to each other as such, instead of their names. So mom would call dad "dad" in front of the children so often it becomes the name they normally call them even away from children. I've also heard mom and dad call each other "wife" and "husband", respectively.

Because that's what she calls her husband. I've heard old women refer to their husbands as daddy or something similar before, so it's not that unusual. It is pretty funny, though.

I realise they are a couple but am asking if and why she is screaming for "daddy"

He wasn't supposed to be her father; they were an old couple.