It's tempting, but there's really only just so far we can go as ''strangers' on the internet when dealing with people's privates lives.
I'd be happy if someone did it for me if I suddenly disappeared .. but not everyone would,. I feel that some people would be horrified at the thought that random people could track them down regardless of the circumstances.
I feel ok with contacting Jim, because we've been friends for many years.. even before this forum, but only online, I kinda feel I would be stepping over a line by contacting authorities to check on him.