I agree. Just be there. Whatever makes her comfortable. Do what she says.
Could be weeks--or hours. The pulse and respiration rate will adjust as the body can support.
Intake might go to zero, so keep lips and tongue moist with a sponge or swab.
Lots of touching, hugs as tolerated.
When my Krissy was in her last days, she was in a hospital bed in the middle of our TV room where everyone normally gathered, so she was always a part of our family and could see everyone all the time. Behind her, out of eyesight, we kept all the emergency equipment, meds, tubes, and 20 bottles of oxygen I don't think we used.
I rolled a little bed next to her, and put it up on wood boxes so that the little bed (mine) was level with hers. This way, we were in each other's view and could touch easily.
She slept nearly all the time, and once or twice had enough energy to sit up and manage a kind of conversation with blinking.
Although she refused all tubes, feeding, trach and everything, she did agree to a catheter so we wouldn't have to clean her up or lift her out for toileting. The catheter emptied into a bag under the bed. Urine turned dark and cloudy, almost chunky, as her organs shut down over a couple days, I think.
She had ordered, in writing months earlier, that if she had air hunger and needed oxygen, we were to give her morphine instead. So although she wasn't getting much air, she was so relaxed she didn't care. No pain, no panic, no fear.
At one point, our nurse said "soon" so we gathered all the family together bedside. We held her hands as her breathing and heartbeat faded to zero. There were some tears, some nice words, and I called the funeral home to come pick her up.
I hope that helps.