Two of the next of kin cases I worked on, involved people who died more than three decades ago. One died in his teens, and his sister worried and grieved for him her entire life, never knowing what had become of him. By the time I'd found located their family connection, she had passed away. In another case, a daughter searched the internet for over a dozen years hoping to find her father. Only when I spoke with her, did she learn that he had died while she was a small child.
I am not affiliated with nokr.org but it's endorsed by the United States government, FEMA, the International Red Cross, the International Association of Coroners and Medical Examiners, and dozens of other legitimate agencies. It's free and easy to register who you want to speak for you when you can no longer speak for yourself. It provides a wallet card and decals to place on your identification so they can contact your next of kin. It's recommended for children traveling alone, those with memory impairment, those traveling out of their area, and during natural or national emergencies.
Go sign up. It only takes a moment, and it may save your loved ones years of worry and grief.