Hi
@Sandymuddle and welcome to Dementia Talking Point. You'll get lots of help and advice here, it's a very supportive community.
Your mother sounds so much like mine, physically very fit, and able to appear capable and able to manage her affairs. It only gradually dawned on me over a couple of years what was really going on, and I never really got to the stage of having the sort of assessment you seem to have managed to organise for your mother as mum was convinced there was nothing wrong with her, in fact she told all her friends I had Alzheimer's which was why I was, in her opinion, being so horrible to her.
The most important thing to organise if you haven't already is
Lasting Power of Attorney. That will enable you to help your mother manage her affairs. The fact that your mother has a diagnosis doesn't mean she can't still have the capacity to agree to it. We organised it through a solicitor as that is what my mother wanted, but you can do it yourself which is much cheaper.
Secondly take a deep breath and don't rush into anything such as moving her in with you too quickly. Is she managing to live independently at the moment? My mother was needing more and more help, but refused all idea of anyone coming in to help with cleaning etc. She allowed me to read her post as her eyesight was bad, but doing anything that suggested she wasn't capable of managing her affairs was very tricky. From the time I became seriously concerned about my mother's ability to manage, to her moving to a care home was about eighteen months. I finally moved her because she was going out to the local pub drinking with random men she met there. I chose a care home, as mum would have thrown carers out, and they wouldn't have been there at the times she was likely to go off in search of company. I didn't consider for a moment having her live with me. She'd stayed with me for a week about the time I began to get really worried about her and I realised it just wouldn't work, even if my husband had agreed. Don't feel guilty if you do decide that a care home is best. Yes, it is difficult at the moment, but things should ease over the next few months. It might be worth finding out about a few, many have videos you can see. If your mother can be difficult be honest about it. I told the home about my mothers spectacular meltdowns and they said they could cope, but it was touch and go for a while if they could. She's been there getting on for two years now, and finally seems pretty happy and settled, though of course I haven't seen a lot of her this last year. This site
Care Home UK is a very useful place to start.
Finally I'm sure others will be along with their experiences and suggestions, but we have a very useful stick round here to beat the guilt monster with. I think it might be your turn to have a go with it.
Keep posting.