I am sorry for your situation OP.
Earlier this year, my 94 year old mum died at Broomfield Hospital in Essex.
Having been admitted to the hospital a few days prior, my stepfather, who was her main carer, and my sister and I were called to her bedside in early hours of a Saturday, because her oxygen levels had dropped in the night and the doctor was concerned she wasn't going to pull through.
When we arrived, it was clear that my mum, with her fluctuating capacity, did not understand the importance of keeping her oxygen mask on. With our support, gently coaxing her to put her mask back on, she gradually recovered, and within a short while her stats were okay again and she seemed stable.
Over the course of the next twelve hours, we stayed with mum and saw her continue to improve and her reliance on the oxygen decline, although she still needed almost constant reminders to put the mask back on.
Then quite suddenly, and without warning or time to prepare and say goodbye, we were told mum was going to be taken to a closed Covid ward and we needed to leave. We pleaded to allow one of us to stay with her to ensure she kept wearing her oxygen mask on, as otherwise we knew she would remove it and would deteriorate again. We were terrified she would die afraid and alone.
We were called early the next morning to say mum had badly deteriorated in the night, and we had a choice. Either accept she was at the end of life, and then we could go into that same closed Covid ward to be with her when she died. Or, one of us, would be allowed one half an hour visit, again in that same closed Covid ward. It made no sense and wasn't really a choice.
Mum died with us around her, in the closed Covid ward they told us the night before we couldn't enter.
We'll never know what that night was like for mum, and whether she might've pulled through had we been allowed to continue supporting her to wear her mask.
The experience has devastated my stepfather, who is full of regret over ever having allowed mum to go into hospital in the first place. And I am haunted by it all.
I hope your mum recovers OP and you can find a way to be with her again soon.