Caring for Mom with End Stage CHF. Any advice?

I am so very sorry. I would ask all these questions now of hospice, and since they have volunteered their suspicions to you, I would be very frank to ask them for all the care help they can give you now. You will also have decisions to make with such things as comfort versus another day of life. For myself I would wish my family to keep me fully medicated so that I didn't experience air hunger or distress. This may hasten death by a few days, but will there will be peace in the passing, not trauma and anxiety. Let your hospice, who knows this case, be your guide.
Very often, in last days you will not discoloring, dusty extremities, and cooling of extremities as the body moves all defenses into the core. There can be confusion and picking at covers; ask to have medications to bring peace below the level of dreaming when possible.
Again, I am so sorry. And yes, family should be informed of what Hospice has told you. There are no guarantees in this sort of thing. Just let them know what you have been told.

My dad passed away this summer from end stage CHF, at home on hospice care. Once he couldn’t get out of bed anymore (he was a very frail, rollator dependent walker), he quickly stopped eating, then his fluids went to very minimal, and he died within a week. The last few days he communicated very little, slept most of the time, and it was a more deep sleep he seemed to be in. I used the meds hospice provided with their instructions to keep him comfortable and he died without pain. Don’t hesitate to ask more questions of the hospice nurse anytime you think of them. Hospice guided me throughout or I wouldn’t have known what to do. I was told the three most telling signs for end of life are loss of communication, loss of nutrition, and deeply sleeping, and that proved true for my dad. I wish you peace as you walk through this, it’s so very hard

"Weeks" is an enormous time frame, to be honest. I don't know what the hospice nurse is seeing that tells her that. "Weeks" could be two weeks or two months, so until she's showing real symptoms of transitioning, I don't know how to pinpoint it any better.