I definitely know what you mean about feeling emotionally exhausted. I imagine most of us have been there! I find that when dealing with dementia, it often feels (no matter how much I know I am doing the right thing) that whatever decision I make is wrong.
I've not been in your exact situation of course, but something similar. My mother lived 100 miles from me and refused all help, except what I could offer by making (increasingly frequent) visits. Even then, I was very limited as to what I could do. I ended up waiting for the crisis, which came in the form of a hospital stay (US version of sectioning) and she was then deemed to need 24 hour supervision and residential care.
The social worker at the hospital and at one of the care homes I looked at, told me very firmly to find a care home close to where I live. While at the time it felt awful to move her away from where she had lived for over 50 years, it was the right thing to do. She has no awareness of where she is, and it's much better for her to be 15 minutes away, rather than 1.5-2 hours. This is especially true when she is in hospital, needs to go to doctor's appointments outside the facility, or even just when I need to go and drop things off for her.
So my first piece of advice is that if and when the time comes for residential care, find a place as close to you as possible.
I will also say that my mother resisted residential care and never wanted it and protested loudly. However, once she settled in the care home, she thrived. At home on her own she wasn't coping, wasn't safe, wasn't washing, wasn't eating, wasn't sleeping, wasn't taking her medications properly which caused no end of trouble, she only went to the same two shops, and was alone and anxious and frightened and unhappy all the time (and I was getting the multiple phone calls every day as she couldn't remember anything). But once in the care home, she was able to eat and sleep on a regular basis, and got her medications on schedule, which made a HUGE difference. She enjoys the outings and activities and has a "best friend" with whom she spends all her time, so she is never alone. Her anxiety has decreased by about 85%, she put on weight, and while she will never be happy, thanks to the dementia, she is as content as it is possible for her to be. Best of all, she is safe and properly looked after, and I can sleep at night.
So, a care home could work out, and it doesn't have to be a negative experience. They are not all the same, and you do have to choose carefully, but I just wanted to share a "success" story, as it were. I wish I'd been able to get my mother into care a lot sooner, in fact.
I have no personal experience of arranging at home carers, but of course it can be done. The trick is to make sure you always have coverage, and a back-up plan in case something happens. You can either use an agency or hire private carers yourself, and of course there will be pros and cons to either approach.
I will say that like your father, my mother has no understanding/awareness/comprehension of her dementia and the fact that she can't look after herself. In her case, it's not denial, it's anosognosia, which is very common in PWDs (persons with dementia). But it did make for some tricky conversations earlier on, as she was "fine" and "didn't need help" and "just wanted to be left alone at home" and all that. This is where some love lies about "just until the doctor says you're stronger" or "the roof needs replacing so we've arranged a stay here" or "the house needs a new boiler" or whatever, might come in handy. And always, always, ALWAYS blame the doctor, the hospital, the National Health, the council, anybody but you.
Very best wishes and hope you can find a way forward.
