Mom is bedridden with health issues. How can I, with health issues also, continue on?

Needing input. My mom Ethel has gone from a staggered walk, to bedridden in under three months. I live with her, disabled, and so does her granddaughter, which isn't, but works morning to afternoon. I am not new to helping, caring as such, but it is taking a toll upon all, including another niece who shares her time. Mom has a uti infection (being treated via antibiotics), incontinence, arthritis, sleeps alot, though recently starting to stay awake and stare into the air. Her cognitive side has literally drained from her, speech or talking is barely undersrtood. With a host of other issues, like grief for years never addressed really, her PCP says all is normal as is her Bp and Temp checks I do every other day are. with shallow breathing, no copd, (pulmonary, neurologist, cardio visits pending), as well as altc in-home care in eligibility phase, I am no good to her a lot of the time when I am sore, going to pay bills, food shop etc... My nieces and I are doing our best, thank God, but we are getting whipped sideways. I let them know, and will again, there are other things needed for their grandma's comfort too, sweeping mopping, sanitizing, and such. I feel they are, to use a phrase I heard having 'Empathy burnout' I too at times.
I cannot lift her out of bed, they cannot either, to get mom to the ER. Paramedics came three times and she/mom refused again and again to get checked out more thoroughly. We all love to do something more for her. Asking for input please, she barely eats but will with finesse, but can hardly suck upon the straw now when offered water or what not. Their lives, I feel as an uncle, could be better enjoyed with each other or window visits with their Mom, my sister, who suffered a major stroke three years ago, at a care home. Thanks for hearing me.