There are a couple of ways to approach this. You can focus on research that has already been done, or you can survey elderly people in your community who live alone. That may be difficult, especially if you live in a small town or you don't know many people, but it can provide you with valuable information if you can get enough people to take the survey.
You also need to decide what you want to know about those elderly people who live alone. Are you interested in their health? Their safety? How they handle daily life tasks or emergencies? Who they call if they need help? Their finances? There are many angles to explore, but narrowing your topic down to one of them will make for a better paper.
