Shedrech nailed it how I'm experiencing stuff with Mum these days and have been discussing this very issue amongst all of us who care for Mum.
It is a feature of Alzheimer's that they recognise you in some way but have lost touch with who you are but they know you are someone they can trust and you are a "safe" person.
My Mum has a family photo on her sideboard. She no longer can understand that the person in the picture is me. She keeps saying "that's <myname>". But has no ability anymore to realise that the person in the picture is the person standing in front of her. Yes, I've aged, and yes I've changed but it seems she can no longer relate to me in person as her brain can't compute.
I've been going round care homes, recently because I think we're now at the stage where we can't care for her anymore even though we have carers in 3 times a day.
The care home shared that if your Mum recognises you in the pictures with what she sees and knows in front of her is you, then she's middle stage alzheimer's. If she can't reconcile you with the pictures but still refers to you by name, she's late to middle stage.
If she looks at herself in the mirror and says "Who is that person?" then she's towards the end stage of middle Alzheimer's.
I've got 2 brothers (one just 5 minutes away) in addition to me who is 2 hours away. Agreement is that brother1 closest by, to when leaving work, drop in on Mum for 30 minutes chat and cup of tea Monday to Friday. I do 10 hours with her, on a Saturday do her cleaning, sorting stuff (feature of Alzheimer's), take her out (so she doesn't lose contact with outside world), do her washing, do her shopping with her (again me taking charge but so that she still knows what shopping is all about), make her food and so on. Brother2 does Sunday and does the same as me for the same period of time.
We've been telling brother1 for over 8 months now that she has no idea who we are but knows we are a "safe" person. Brother1 says -- "She knows exactly who I am, and it's because you don't see her regularly enough".
Brother1 had health issues and could not longer support Mum so we put carers in immediately to replace him at exactly the time he would have been there.
The result was that for a few days Mum would ask the carers - "Where is that man who used to be here?". She would sometimes ask me at the weekends "Why isn't that man seeing me?" But otherwise she just accepted that the carers going in were girls and that they were "safe".
Brother2 and I have accepted, as we did many months ago, that Mum has no idea of who we are. She knows we turn-up and look after her and sometimes get really angry etc and throws a hissy fit a bit like a 2 year old if we don't do things her way. Seems along with Alzheimer's is a bit of OCD.
It is a rubbish feature of Alzheimer's that they won't know you. It's hard to get your head around that but yes it is something you must if you want to protect your sanity. My brother2 and I talked about this all the time when we first realised this was happening. It hurt us both and we struggled to come to terms with it. In the end we both agreed that we are caring for someone who has no idea of who we are . Because we love her and she is our mother we need to take care of her and do the best for her but we're not qualified to deal with someone with Alzheimer's.
We've contacted her GP, Social Services and memory clinic and we've been told that basically - we're on our own. It's great that Alzherimer's UK provide this forum.
Azheimer's is a rubbish disease that seems to not be recognised by govt or have in place anything to support those of us going through caring for loved ones with this disease.
But the fact that you've asked this question and have already realised to some extent recognise that she no longer knows you and have reached out to this forum is brilliant. We can't give you positive answers but we can share experience and it's horrible to realise where things are at but it's fantastic that you've reached out and hopefully have a bit more information to help you and please realise that when caring for someone with Alzheimer's is hard on you, and please do take care of yourself.