There are many causes for CHF, and just as many responses to treatment, depending on the patient.
You are spot-on to contact her MD for a thorough history, examination and possible further testing, along with initiation of treatment of the underlying cause(s).
Some people live for many years with CHF; again, it depends upon the underlying cause and response to treatment.
We are not qualified to offer any medical advice, however.
I hope she can be seen in a timely manner and that she responds well to treatment.
All the best,