Dear Carol,
Oh dear, not the news you wanted to hear on your arrival.
I agree, it sounds as though the medics are doing what they can for your Mum in treating her as an unwell person, and seeing past the dementia. All they can do is try, and it should hopefully bring your mum some comfort.
Sometimes it just seems to keep coming in spades, doesn't it? Just focus on today, and getting through that. I hope the antibiotic starts showing some effects soon.
Best wishes x