He was told his heart was functioning at twenty five per cent. what might be the prognosis?

Better than before: In past times, 25% ef was very worrisome, but with modern treatment, it's manageable. Everything you read about prognosis will be outdated and wrong because this is a rapidly changing area so don't be upset if you read pessimistic information on the internet. Get hooked up with a cardiologist - good luck!

Ejection fraction: An ejection fraction of 25% will leave a person significantly less able to get around fast on their feet, but if the cardiac disease is not progressive, may be compatible with many years of reasonable health. As usual, a number is much less important than the big picture.