Sorry to hear about your Mum. I hope she is able to slip away soon and that all are able to be at rest and peaceful.
I'm not sure about my Dad - was he very weak or was he actively dying? We knew the end was near - he'd been announcing it - but not exactly when. It's not a science.
In the run up to this there had been upset about a DNR notice a few months previous to his final days. - We (my brother and I) did not have any issues with it. His illnesses had varied in their intensity and effects upon his life, any of them could have taken him.
We, (me, my brother + Mum) had been sitting with him day and night for quite some days in his final fortnight. In shifts, me mainly at weekends. He slept a lot of the time, spoke briefly at others. He'd given up eating and drinking some days before but we kept his lips and mouth wet.
I lived a couple of hours away and was still working. He'd announced his imminent death several times over his last couple of weeks, and I'd dropped everything to go over only to find that he was much the same; poorly, weak, declining but still going.
My brother and I decided that we couldn't carry on like this and he would call me if he was actually going. We had also decided CPR was out of the question and its violence would have been cruel to a dying 87 year old man, similarly we weren't going to call 999. We had assistance from a home hospice if we needed more help.
Eventually he slipped away quite quickly, quite peacefully with my brother and Mum with him. My brother called me and I went across.
It's a hard time with different pressures and emotions present on the run up to the death and different ones afterwards.
Everyone is different - both the dying and those left behind.