Dear Patco,
I can't tell you how long your dad has to live (no one can) but I can give you an idea about prognostic factors. For individuals with class 4 heart failure (fatigue at rest) after 5 years more than half will die. If the individual has kidney failure the mortality doubles over that period. Low blood pressure not due to medications carries an increased risk as well. Hope these numbers help. His doctors can probably give you a better time frame (e.g weeks, months or years) to help in decision making as well. These are difficult decisions and I would encourage you to also discuss things with your dad. The most important thing is to try to follow what his choices for end-of-life care may be.