Oh Kath, I am so sorry to hear this news, it must be shocking as much as you prepared yourself for it. As it will turn out, you WILL find the strength to get through, it comes from the very core of you and there is beauty in giving back to our parents after all they have given to you.
The most touching moment I had with my mom was when we brought her and my dad down to FL, my brother and I. You see, we had learned how precious time was and to seize every opportunity because we had been through it having lost our youngest brother only months before mom.
Yes, it felt as if the wind had been knocked out of us but somehow we got ourselves up and went back into the ring....to fight the next round.
So the moment I wanted to share with you was when my mom couldn't bath herself, she was still able to stand up pretty well and I took her into the bathroom with some Bath & Body works lavendar scented gels, lotions, etc.
I cleaned her up ever so gently and she cooed and thanked me up and down. I know that it was somewhat difficult for her to allow me to reverse roles and I made light of it saying how she was at "Ivory's Day Spa" and she deserved to be pampered for a day!!

She truly enjoyed that pampering and there was such beauty in being able to do that for her and share that moment together as mother and daughter.
The other moment was when each night my brother and I would tuck mom and dad into bed. Mom was unable to get to the lying down position without alot of pain but if one of us supported her back while the other lifted her legs it made it more tolerable.
Each night we did this and there came a night that my brother and I were watching the Olympics and my mom called out to us telling us it was time for her to be tucked in. How often is it that two grown children get to tuck their two elderly parents into bed???!!!
Such precious memories that make me so glad that we seized that opportunity, dropping everything else to have that precious time together as a family.
Turns out that mom passed only weeks from that week we seized together as a family. My brother and I made up an album of pics for mom to bring back and she told us it was the best vacation she ever had!! And it was.
So, Kath, as BlueDiamond points out, you will need to micro manage this using the resources available to you and take that time when you most need it.
Perhaps having a dedicated time that is yours with your mom (lunch or dinnertime) that each of you look forward to around the nurses and other resources will work out.
With us, I was snowbirding in FL, trying to take a respite from losing my youngest brother and flew up when mom had some procedures to be of extra support to her and Dad. My brother lived about an hour away and would visit in between. We filled in the gaps together so you might try to assign times that your brother needs to fill in a little bit as needed too.
Sometimes, other family members just don't know what to do unless told to in situations like this and that may be how it is with your brother. Try it out, tell him that your mom needs somebody to be there for this or that when you cannot giving him some notice to clear his schedule. I think that in the future he may be very thankful to you that you assigned him such times so that he could be a part of this journey.
I wish you love and special moments as you make this journey with your mom. Remember how important it is to take care of yourself too....putting that oxygen mask on yourself before you assist others, something we sometimes forget to do.
I hold you and your family in my thoughts hoping that as you journey through the months ahead that you find precious moments that you will tuck into your heart from which to pull from when her time finally comes.
((((HUGS)))) ~ Ivory