It is difficult to assess the exact survival period. But more alarming thing in your query is 18% function. Most probably what you meant is 18% Ejection Fraction
of the heart. Normally it should be 60-65%. With such a low EF quality of life will be lost. He will have heart failure
symptoms like water logging and limb oedema. Strict medication will help. He should be free of salt in diet with control of water intake. It is good that he does not have VF episodes for last one year.