The Biological father of my son died years ago. How do I go about his family influencing in his life.?

They havent been there since he was 1, and all of a sudden they want to be a part of his life. We have a very happy and stable home, and Im just not sure its in his best interest for them to reappear. But I dont want to be out of line so I ask for any suggestions from people in similiar situations. Thanks