"A & E for dementia patient"

My mother had a fall at her residential care home on 19 July 2019 and was eventually taken into A & E by ambulance at 7 pm. My other is 89 and has dementia She had badly bruised her cheek and eyebrow area and quite rightly the hospital wanted to do scans and other tests to ensure that all was well.

I went to see her at 10 pm that evening and was told by a doctor that there was a queue for the scan but as soon as they could she would be settled for the evening and taken back to her care home in the morning. I relayed this to her, she seemed to understand and was quite happy. I went home.

At 4.21 am I was called to be advised that my mother was being discharged and would be taken back to her Care Home. She has just arrived at 10 am upset because she thought that nobody wanted her anymore!

My questions.1. What was the purpose of the call to me at 4.21 am? Was I supposed to transport my mother back to her Care home in the middle of the night or was it for statistical reasons? 2. Why would any decent hospital even contemplate discharging an 89 year old lady who has dementia in the middle of the night?