My Mum went into a care home after knee replacement surgery. We had managed to keep her at home until that, often with very difficult situations, where she did not know my Dad (or me after I came home to help) and threatened to call the police. Generally, she would be more reasonable when we called my sister over (who my Mum thought was her own sister). When my sister came, my Dad and/or I would generally have to leave the house before Mum became too upset at the strangers in her house. We could usually come back later when she had reconnected and wondered where her husband had gone.
We had hoped she could come home after the knee surgery, but as soon as she had had the surgery she forgot about the operation and the crippling arthritis she had suffered with for years and became very antagonistic about being kept in the hospital, blaming my Dad for this. He realised he could not cope with her at home anymore, particularly as she rejected his help know for showering and also refused the carers we had tried to introduce before. She believed she had no need of help.
When she first went in the care home, we tried the explanation that she was there for rehabilitation after her surgery, but that had limited impact, as she had forgotten the surgery, even when we showed her the scars on her knees (it was double replacement in the same operation - which fortunately ended her pain so eventually she came off the high doses of painkillers to occasional paracetamol).
We stayed away for a couple of weeks so she would become more accepting of the place. Sometimes she was very difficult with the carers during this period, even once threatening the break the windows if they did not let her out.
When I went back after the two weeks, she was less distressed, but still didn't understand why she was there and said she wanted to go home. When I asked who was at home, she said her Mum and Dad (who had died many years before). This was why she lost me and my Dad when she was at home - she was adamant she wasn't married and didn't have kids, because she would obviously have remembered. This made clear the impossibility of taking her home - the home she wanted and expected no longer existed. Her being in the care home was not a case of abandoning her, it was the treatment required for the illness. My Dad found it very comforting that even though my Mum was occasionally angry at being there, she never showed the fear we had seen when she was at home and didn't know who we were.
It's worth considering when trying to come up with an explanation for your Mum that she may be living in a different time in her life and explanations that you think might help may just be confusing.
Early on, I found it often worked not to try to provide an answer, but to say, "Oh, you told me you were staying here for a while, so I thought I'd call in as I was passing. Is that okay? Is this a good time?" Although it didn't help end her confusion, I think this at least gave her a sense that she was in control, even if she couldn't quite remember why she had decided to go to this place. Then we could talk about other things.
If she became insistent on leaving, that meant it was time for me to go. So I'd say something like I needed to go back to work so couldn't take her straightaway, but would come back later. That might seem unfair, but I knew she would very soon forget I had even visited. The carers were always very good at going to see her to distract her when I told them she had been asking about going home.
After discussion with the carers, we took her out for lunch as a regular thing for several months. A carer came with us the first time. So sometimes when I visited and Mum said she wanted to go home, I suggested going for lunch, and she liked that idea. We went to places she was used to and met up with other members of the family.
Then we'd go back to the care home and say we needed to call in to see someone. She'd forgotten the place and would willingly return. Inside, we could take her to her room and ask if she wanted to have a rest for a while. Generally she would. We never had any problem taking her out, but over time she found the trips out more and more unsettling and the places visited unfamiliar, so the trips out reached a natural end.
I still referred to trips out at other times to give my Mum a sense of control and freedom. So I might say I couldn't take her with me that day, if she was insisting, but we could go out for a picnic tomorrow. Then I'd keep talking about where we might go for the picnic and what we might eat until that became the topic of conversation.
The care home has a separate dining area. We visited outside meal times and so could use this space and if she was wanting to leave, it sometimes worked to say. "What about going to the café?" We'd bring in something to eat and could make tea. As it was a new place to her, it would be like we had gone somewhere and would be a distraction.
She has now been in the care home for nearly two years. She has gone through different phases with the progression of the Alzheimer's. Sometimes, the mental health nurse has suggested medication to help. Mum stopped asking about going home (or did so infrequently) a long time ago.
Then, I would generally ask her what she had been up to and she'd talk about being very busy, working around the house, or going to the shops. She'd also talk about helping her Dad in the garden. So even though we weren't taking her out on trips she would soon forget, she was having an active life with the memories that came to her. I found that to be reassuring.
Now, when we visit, she doesn't know who we are, but likes the company. Whoever goes takes a cake and she will sometimes refer to it, saying, "Did you bring me that thing?" After a while she'll close her eyes and agree she needs a rest when we say we have to go to the bank or sort out the car. She'll often say, "You do that and I'll have a rest here."
With regard to telling her the truth, although she had no awareness of her Alzheimer's, she did acknowledge "memory problems". So on one visit soon after the first two weeks of not visiting, when she asked if I could take her home, I asked if she knew who I was. She said, of course. I asked her what my name was. She said she couldn't remember. I said, "Well, that's the problem, because sometimes you don't remember who I am and get scared, so you are staying here for a while where you won't feel scared and can have a rest." She asked then if she had a room and I took her to that (this conversation was taking place in the garden). When she saw the bed, she asked if she could lie down and have a rest. This was an exceptional conversation though - and followed a couple of other honest conversations at home where she had given revealing insights into what she was experiencing. But it was interesting to see that in the moment when she had some awareness, she was glad to have a room of her own to go to. Even though it was a surprise to her that she had a room, it did imprint on her and she soon felt safe and relaxed there.
