The Service flag may be displayed, in a window of the place of residence of persons who are members of the immediate family of Service members serving in the Armed Forces of the United States
during any period of war or hostilities in which the Armed Forces of the United States may be engaged, for the duration of such period of war or hostilities.
"Immediate family member" is defined as: wife, husband, mother, father, stepmother, stepfather, parent through adoption, foster parents who stand or stood in loco parentis, children, stepchildren, children through adoption, brothers, sisters, half-brothers, and half-sisters of a member of the Armed Forces of the United States. Unfortunately, the definition does not include grandparents.
The Service flag may also be displayed by an organization to honor the members of that organization serving in the Armed Forces of the United States during any period of war or hostilities in which the Armed Forces of the United States may be engaged, for the duration of such period of war or hostilities.
"Organization" is defined as group organizations such as churches, schools, colleges, fraternities, sororities, societies, and places of business with which the member of the Armed Forces of the United States was or is associated.