I'm not a PWD, I'm only caring for one, however I have a lot of sympathy when it comes to this, as when I am stressed and overwhelmed (which is a lot of the time at the moment) my memory and cognitive abilities deteriorate to such an extent that it frightens me, although I am getting more used to it now. People i know well think I'm joking when I describe it. I don't worry enough to seek medical advice because if I do ever get to relax for a day or so and get plenty of sleep, it gets much better and I don't have any significant issues then, so I'm pretty sure it is just stress and sleep depravation in my case. I do find it curious though (when I have time to think about it) which things I can remember very clearly, and which things may as well have never happened.
There is clearly some subconscious filtering going on with me which determines whether or not something is going to stick in my head and I guess it is the same for PWD. I can often sense at the time which things I'm going to remember and which things I just won't, and I'm absolutely powerless to change which bucket they fall into, regardless of how much I want to.
I'm hyper vigilant when it comes to anything related to finances or when watching out for the reactions and behaviour of the relative I care for because I'm so scared of messing up, so I am usually very confident in my ability to recall things relating to those things, as I normally remember them with great clarity and can recall them off the top of my head without trying. However, names of people I met since the start of the pandemic are impossible for me to retain without a massive amount of repetition and even then if I don't see that person for a few months I'll forget again. Most appointments are impossible for me to remember too so I have to check my diary about ten times a day ( I missed a dental appointment today despite only booking it yesterday!). Even things I desperately want to do such as a yoga class I will forget unless I set an alarm, and even then I am prone to forgetting a few seconds after the alarm has gone off if something distracts me. I have to put post it notes up and write on my hand in order to get the bins out on the right day (writing on my hand is the best method!). I'm totally reliant on my to do lists, and I forget to eat unless I'm hungry, but on the other hand I can always remember very well exactly what I have eaten and what I have in the fridge.
There is a badminton class near me on a Friday night at 8pm which I love going to, and the most wonderful group of people attend and they always make me feel so welcome. There is a huge age range and some of them have autism and learning difficulties so it is very inclusive, and they are incredibly kind, supportive and non judgemental but I rarely go because I'm always absolutely shattered by that time on a Friday evening and it's not just the feeling tired that prevents me from going, but the problem is I just can't bear to risk hurting their feelings by coming over as uncaring or giving the impression I'm not interested in them, because I can't remember their names (I first met these folks getting on for three years ago and have written them down and I have no health conditions or disabilities myself, so I feel I have no excuse) or I can't hold up my end of the conversations. I know I will not be able to remember all the things they told me the week before so I will neglect to ask them about their holiday or something significant that they confided in me, such as a funeral they were nervous about attending or whatever. I care deeply about these folks and would love to spend more time with them, but something in my brain has decided that these interaction are not priority when the memory bank is getting full, and however much I try I can't remember enough to be able to interact with them in the way I would like to and my fear of coming over as rude or self absorbed or uncaring outweighs my very strong desire to join in, which is really sad.
It's the same with close friends and family members, although fortunately they repeat themselves quite a lot and don't wait for me to ask questions or show an interest before they tell me what's happening with them, so that helps me out a lot!!
I do think there is some kind of selection process going on that determines what I can remember and what I can't, but it is not conscious and it's not something I have any control over. It certainly isn't based on how much love I feel for the people I am interacting with. I hope in sharing this it might help / reassure a bit.