My Uncle Has End Stage Heart Failure. This Is What

My Uncle has end stage heart failure. This is what his Cardiologist tells us. He is 59 years old & had a bypass about 9 years ago & a pace maker put in a year ago. He collapsed last Monday cos he felt weak. He was admitted & his now on Warfarin. His heart function is 22%. How much time does he have left? And how do we make him as comfortable as possible.