A reliable archive for Russian textbooks. You can find the 5–6 Parent's Book and the Spotlight 5 Exercise Collection here in PDF format.
You can find various parts of the Barashkova grammar series—including the (Exercise Book) and the Kniga dlya Roditelei (Parent's Book)—on several educational resource sites: A reliable archive for Russian textbooks
Barashkova isn't a "one-size-fits-all" book. It is designed to supplement specific school textbooks. Make sure you download the version that matches your school's curriculum: Vereshchagina / Afanasyeva Spotlight (English in Focus) 🌟 Need Extra Practice? A reliable archive for Russian textbooks