Well according to your description, Your father is included in NYHA (New York Heart Association) Class 4 which means shortness of breath
at rest. and ACC/AHA stage 4 or D which means Heart failure
refractory to treatment and requiring special intervention.
Life expectancy is defined in medical terms as prognosis. So the statistical numbers depending upon the above mentioned stage are as follows;
1- 30 day mortality due to hospitalization with heart failure is 10%
2- 1 year mortality is around 22%.
3- 5 year mortality rate
with stage 4 is around 43%.
Each hospitalization increases the risk of mortality to 20%.
Hope that answers the question, In case of any queries, please do not hesitate to ask.
Thanks and God Bless your father