I absolutely agree with getting a power of attorney- NOW. Not just for medical things, but financial also.
In hindsight, I wished we'd employed a cleaner much sooner- to give my mum a break.
I also wish we'd moved nan to a care home sooner- to get her used to the layout and be more familiar with it and the staff- before she declined further. Also- by that point- my mum was visiting daily, emptying a commode, doing all the washing and cooking and helping nan dress etc.
Whilst still living at home, nan ended up with a UTI and in the middle of a winters night, walked barefooted in a summer nightie, up the a neighbours house. She asked them for a long ladder because she thought her daughters (in their 70's) were playing on the roof! She developed pneumonia and we thought it was the end.
People worry that relatives will decline in a care home, and obviously some are better than others, but my nan lived for another 5yrs there and died at 102.
Age UK or some of the dementia specific charities could provide more advice too