Question about Congestive Heart Failure?

My husband's grandmother is 85 years old and we living in a nursing home due to severe confusion and dementia. We live in TN and she lives in OH so we aren't there to talk to the doctors. Her son sends us emails very frequently to update us on her condition and we just recently found out that she has fluid around her heart and lungs and is in the later stages of congestive heart failure. Her son has called hospice in along with her care at the nursing home. He said she is currently on medication for the fluid but it will eventually quit working and there will be nothing that they can do for her! We are very close to her and my husband and I are beside ourselves worrying how long she has left but we do not have the heart to ask his uncle how long they think she has left. Does anyone have any experience with this? Or how long she may have left? Thank you so much!!!