While they may not seem all that important in Benny's universe at first, considering they spend a lot of his life dead, they do often appear as flashbacks and in the form of ghosts, as well they do play quite a part in Benny's life, being his "aunt and uncle from another family." No, they are not directly related, but they treated Benny like a nephew.

"Mr. and Mrs Wulve
Benny's unofficial aunt and uncle. Benny remembers these two very fondly, as they would often share a pot of soup. They were two more people who admired the inocuous lapin. They are no longer in the land of the living, but Benny will never forget them. Benny still visits their abandoned house."