What is the life expectancy of someone with advanced heart failure?

[Kelbel1]

My step father is nearly 84 years old, he hasn't had a thing wrong with him in his whole life up until now. He went into hospital last week with shortness of breath and swollen ankles and tiredness. They said he had phneumonia and a crackle on his lung which he is being treated for; and also they have said he has heart failure. They've given him a fair few kinds of medication to take and have sent him home with his discharge notes. When he got home myself and my mum read the discharge notes to find that under the risk assessment section it says "patient is at risk of dying in the next few months " and also mentions that his doctor should sort end of life care out. Firstly how SHOCKING to get home to find this information on his notes without him or any of us being told anthing about him nearing the end of his life!!! He thinks he's going to recover! But if this is correct, then how long does he have left? I know no one knows for sure but he is healthy besides this and was driving just last week.