Oooh, I can relate to this. Trying to keep one's tone light and even while answering the same question for the Nth time, yet still being accused of being patronising... sigh.
During the night I was in A&E with my mum, I got the repeat qestion "so where are we then?" - fair enough. However, and maybe it was the bang on the head etc, it wasn't minutes apart, it was seconds. Plus, if I answered it simply ("we're in A&E") that would give rise to a load of subsequent repeat questions. I ended up having a little script that I repeated while trying not to sound mechanical: "we-are-in-A&E-at-****-Hospital.-You-have-had-a-fall-and-hurt-your-head.-We-are-waiting-for-you-to-be-stitched/seen-by-a-doctor/taken-up-to-the-ward.-You-fell-in-your-bedroom-at-***-Road-and-bashed-your-head-on-the-wardrobe." Within around 10 seconds of my finishing this, she'd ask again. I eventually got some peace by pretending to be asleep!