nostr:npub1ykvylvnd2v7lk0eknvf3cypdkcy9j5u5x6avcpuklvgducqcmsqqfmey6z It depends on how much your grandparents are willing to learn. Personally I recommed KeePassXC. Teach them to use auto type. The other option is free plan for Bitwarden. Avoid at all costs password manager built-in to a web broswer. Teach them to never save in browser. Make sure which ever option you go with to have a automated backup solution.