Sometimes I think its also a mix between forgetting the relationship, husband, wife, sister, daughter etc, but also substituting the word for another. Like she might say dad but mean husband... hard to be sure
My Mum has just gone into permanent care.
In the past month she thought dad was 3 people.
My Dad, her husband Dave, and a man called David that lived there with her. Also I was her daughter, and her neighbour, but she could not understand that she was my mother.
If I called dad, Dad. Mum would say whose Dad, my dad? No I would say My Dad, Dave your husband. We would go round in circles till I got to the point of just calling Dad, Dave. All rather confusing
David was the one that she was scared of.... this prompted the sudden decision for Mum to go into respite which turned into permanent care.
She would come over to my house literally shaking, and asking why she had to live with him, why was he sleeping in her bed. Dad could not cope with this at all. So sad