My sister says she has esophageal varices. Are family members more likely to get the same thing?

Liver disease. Varices are seen commonly in liver disease. So it depends on what liver disease we are talking about. For example hepatitis c isn't genetic but wilson's disease and hereditary hemachromatosis are.
Esophageal varices. Esophageal varices is one of the signs of / can develop in chronic liver disease. Most common causes of chonic liver disease are alcohol and hepatitis c or b-- these are not hereditary/genetics. A few genetic abnormality-however can also cause chonic liver disease- for instance---> hemochromatosis, primary biliary cirrhosis, wilson disease.