Poring over the Wikipedia stats, I can tell you that as a rural county that shares part of its land with a Native American reservation and has less than 8000 people, these stats should not come as a surprise. Some people might end up retiring there anyways, but of course, it is absolutely not a place to try and start a family unless you want to homeschool or something.

Great to visit though.

As for "worst counties", there are many other subjective measures, as those in Spokane would tell you "King County". But if we're talking overall misery, I think it's also fair to compare Ferry to those with larger populations.