MANY MANY PEOPLE HAVE A LEAKING HEART VALVE. EVEN VERY YOUNG PEOPLE. IT IS OFTEN CALLED A HEART MURMUR. SOMETIMES PEOPLE MAY NEED A NEW VALVE REPLACED WITH SURGERY, AND EVEN IF YOUR MOM'S VALVE WAS LEAKING THAT BADLY, THESE OPERATIONS ARE DONE OFTEN AND ARE VERY SUCCESSFUL.
Your mother can have a normal life span with heart valve leaking. It depends on whether there is progression of regurgitation, valve integrity, underlying cause, etc. An operation would be appropriate if your mother has severe shortness of breath with very little activity (i.e.walking up a stairway), etc.
I have known about my mitral valve regurgitation (moderate to severe) for the past 5 years and there doesnt appear to be any progression. Some valve disorders can be done successfully without open heart surgery by cath.