Another little update. Mum did, indeed, have an infection in the last urine sample. Her gp phoned her with the result, and mum said that he said "if it seems to be asymptomatic, there's no need to treat it, as it's just a slight infection."
Seriously! Why did he think I sent in a sample? I'm sure mum assured him she had no symptoms, because in her mind, if she doesn't have stinging or burning or pain, she has no symptoms. And he's supposed to ring me and not mum.
Anyway, after several more days with mum's hallucinations becoming, again, her sole topic of conversation, I rang the Clinic in the hospital who had prescribed the quetiapine. They were a bit incredulous, and said "But, if her hallucinations are increasing, then that's NOT asymptomatic!" I had also phoned and left a message for the gp, and they prescribed an antibiotic. Within days, mum had calmed down again. The hallucinations are still there, she says, but they aren't taking over her life right now. Maybe she needs a slightly increased dose of quetiapine.
I have noticed a bit of a deterioration in her memory etc. since Christmas. She's a bit more vague, especially on the phone, which she sometimes doesn't answer at all, because she forgets how. She occasionally was forgetting to take her medication and sometimes taking it but dropping some and not realising. So now, I'm in every evening to make sure she has taken it successfully, and in on the mornings that the Care Assistant isn't there too, to make sure she takes it. She's on so much medication for various health issues.
So, that's where we are now. The quetiapine is definitely having a beneficial effect, but maybe not quite as good as I'd hoped, so far anyway. But of course, this latest infection would have affected that. Mum has serious kidney/bladder problems, and I suppose UTIs will be an ever present feature for her.