Looking for a bit of clarity!

Hi all, I just am looking for a little clarity here and just wondering how much time we have left. My grandmother has stage 4 COPD and was recently in the hospital for 32 days. We moved her into a rehab in the past two weeks. On Sunday morning, she ate breakfast and was talkative. By Monday, she wasn’t really eating or drinking. By Tuesday morning, she wasn’t really waking up at all except for small bouts of lucidity to say hi, I love you, and she kept asking if she was dying. Yesterday around 2 pm, we moved her up to hospice. She wasn’t really lucid at all yesterday and only really responds to I love you which is amazing but so sad. I guess I am just wondering how long we have with her since there’s no clear timeline from her staff. Like how long realistically can someone last with no food? We’ve been sponging water into her mouth for her but nothing else. She also hasn’t gone to the bathroom in over 24 hours. I just don’t want to miss out on anytime with her so I guess I am just looking for guidance!