Without knowing too much,luckygirl I would say she is in a degree of denial- at how serious her father’s condition is and how hard it is for you. She may be speaking with (to her anyway) the best of motives, but she is in fact making it harder for you.
I too have one shall we say “dominant” DD, great at getting things done but expects her idea of action to be mine. We didn’t fall out over a couple of things but could quite easily have done. She is in fact a lot like me, but the other two, (especially DD2 ) are much more empathetic - but DD1 is the one who swings into action.
However hard, you need to sit them down and, as you say try to ensure you are all on the same page. They also need to be on board regarding DNR wishes. Write down all you feel and as far as possible try to keep your emotions out of it. Being chivvied along is in fact a form of (however well-intentioned) bullying.
She also needs to be clear that your DH does not always know exactly what he wants or indeed is possible.
Live in care is an expensive option and as you say, not necessary not even desirable 24/7. Is there somebody e.g.from the Palliative Care team who can outline the different options, pros and cons, based on their experience.
Palliative care need not mean “end of life”care and all the hospices I know of set a 2 week upper limit- and I am assuming things are not yet at that stage.
Finally, a lot of people talk of the “guilt” of arranging respite or residential care. It is not “putting someone in a care home” it is finding the best level of care for your DH.
Both of you need consideration and your children and their husbands do need to face facts.
