I know this isn't going to help anybody, and may come across as faintly patronising...it isn't meant to be, honestly.
I have just spent a fortnight looking after my elderly mother while the family member who is usually there for her had a much-needed and well deserved break. She has carers coming in several times a day, so I didn't need to do anything physical, but I was still on call 24 hours a day, and didn't have the opportunity to do anything else at all. And I'm exhausted, mentally and emotionally. I was appalled at how aggressive and spiteful she can be, and how quickly she got angry when I didn't understand what she wanted straight away. I understand that a lot of it is frustration, but it was still a hell of an eye opener.
So I'd just like to say, to all of you who do this all the time - you rock!!