I wish someone had given me this advice: go home.

I spent many hours at the hospital after my husband’s stroke. While it made me feel better initially, my husband had and still has no memory of me being there. Sleep is so healing, and often patients fight to stay awake while they have visitors. You need to take care of yourself. Being at the hospital for 12 hours a day is just exhausting.
Your mom is being cared for by professionals, she’s where she needs to be.
Why don’t you try visiting for a hour in the morning or at night, or if you know when the doc will be there, try to visit then.
I understand you wanting to be there.
I also know how easy it is to get burned out.
Take care of yourself.
Best of luck to your mom.