Oh OP
the worst vigil I know of amongst friends is about a month! You can't really keep vigil. Are you on annual leave?
I am going to be blunt as that's what I would have found helpful from others. What's the deal with the 24/7, are you doing it because you want to do it or is there some pressure from siblings?
I certainly would have been around a lot less if I hadn't felt pressure to be with mum.
You DO need to pull back.
My situation was also a bit different than yours in that dad should have gone into palliative care about 3 weeks before he did. I knew I would be by his side most of the time, but in my mind, I had done goodbye - we had said it as well before he slipped into being mostly semi conscious.
but my last day of really being focused on him, I was at his bedside listening to music and a song came on, "What Sarah Said". Don't listen to it if you are not ready!!!! Major lyric is "love is watching someone die" - and I suddenly thought, OMD, no can ever say I didn't love him enough, I have been watching him die for SO LONG.
So without my mother, and if they'd put him on end of life at the right time, I would have returned to normal life mostly and maybe gone for an hour a day.
and please don't feel guilty about doing anything normal. Because I was staying with my mum, I didn't get the chance to do anything normal. But the first day I got back to my own home after his death - a week or so? just for a couple of hours to get clothes and check on the place - I put music on and had a little bop!! Because I hadn't been able to do that for 3 fucking months (he was ill a long time generally).
sorry for the ramble. I am just trying to brain dump anything that might help.