Ah, that is another layer of problem.
For instance, at Epsom General Hospital they pulled strings to ensure Dad wouldn't leave alive or otherwise would have to go into a care home, the idea was to have him stuck there and deteriorate to force the issue. We forced the issue by getting the consultant onside which infuriated the then matron - this was on the ACU ward if I recall, and she tried to stop it, going to all lengths. This included having a tall, unsociable NHS worker stoop down in front of Dad when he was in his wheelchair to ask, all friendly, if he wanted to go home? If Dad had said no, suddenly his word would be enough and he'd be stuck there.
In other words, if he agrees with them when put on the spot, he has mental capacity, otherwise if he disagrees with them he does not have mental capacity so his word doesn't count.
Now we anticipated this crap and had a hard copy of the LPA in Health and Welfare about our person, something I suggest you all have in these situations plus on your Smart Phone too to email it.
But... and I hate to say this, there is an argument that you still need to activate the LPA in Health and Welfare and this may necessitate a friendly family doctor to authorise this. Unfortunately some GP practices now refuse to do this - we got it done anyway but you could also argue it makes it clear your parent is also far gone and therefore deserves to be put on end of life care if so, you have to get it worded correctly. I don't like to say this but anyone in the NHS could read this and say, ah, you've got LPA in Health and Welfare but have you activated it?
Btw we got Dad out and he lived another six months but the next time he entered Epsom General Hospital they got him, he was toast within 3 days. I'm not saying he was in a great way at that point at all, but we'd rather he'd gone at home not in Mary Seacole Ward.