One thing everyone should do is post emergency info on their refrigerator, with whom to contact, what ailments a person may have, and what kind of medications they are on, if any. One could also include info on pets and any caretakers who might need to be notified. Emergency personnel are trained to look for this info on the fridge.
Somewhere, in some thread about a year ago or so, some of us agreed to be contact people, by telephone and email, to alert Mudcatters if something happens to one of our own. I couldn't find it the other night and we didn't get really formal about it, but it is good to know that we all wouldn't just be left wondering if one of us suddenly quits coming 'round.