Unfortunately, it's not possible to answer this question over the internet. Your friend's life expectancy depends on many different factors, including what type of bypass surgery she had and how old she was when she had the bypass. Depending on the type of bypass surgery, the grafts can stay open for many years, which may be longer than your friend would live normally. So for some people, bypass surgery might be a cure. Your friend's doctor will be able to discuss her prognosis with her.