The UK Safer Internet Centre provides some support and guidance for grandparents to help support their grandchildren's online safety. These accessible, easy to understand resources provide guidance on talking about staying safe online and help grandparents understand common threats and experiences.
This guidance is suitable for any adult who is not the primary decision maker about a child's internet access but would still like to offer help and support.
https://saferinternet.org.uk/guide-and-resource/grandparents