How does a daughter tell their Mom it's ok to let go, but Mom knows it's nothing but a lie?

Lucky, My heart goes out to you. Please know that for someone as sick as your mother, there are a lot worse things than death. Every day is such a struggle. I can't imagine trying so desperately to just breath.
Yes you can go on without her. That is life. We are not created to live forever. We would hold on as long as we could, but the Lord knows better. You can and will get through this. Sending a shoulder to hold you up for a moment. You can do this. You are stronger than you think. You really are.

I'm so sorry for you both. I don't have an answer, but I feel your emotional pain. I'm caring for my mom as well. She has COPD and is on 2-3 liters of oxygen. She has a multitude of other problems as well. I can't imagine what it will be like if she passes before I do. She's been my best friend since I was born. I wish you both peace.