The only other means of communication which might have led me down the same path on that occasion was a family message board on QuickTopic.

However, frankly, Facebook is much better, for a wide variety of reasons. The message board was never ideal, privacy was a binary choice, people regularly struggled with it, photo sharing was a joke, etc. It's not at all obvious that the short hospital stay would have been communicated there.

Email, phone? Nope, wouldn't have happened.

Has Facebook displaced other communications mechanisms? Sure. But for the most part, the alternatives were far from ideal. Facebook has won by being better.

It's just unfortunate that they aren't satisfied with being a good way of keeping in touch with friends and family.