Not sure what bulk propane goes for these days but back when I was a teen in the late 90s I remember my folks saying a fill-up for the 500gal tank was around $500. That would only be a 3x a year or so, mostly during winter. This was in the upper midwest where it was pretty cold in winter but mild summers so we spent a lot propane for heat a few months a year but very little for electric the rest of the time (maybe a week of AC usage, if that).
I suppose if they have a large tank and big, inefficient house they might get a few bills that high but it wouldn't be all year long. Maybe a contract/lease renewal fee, too?
That kind of lumpy cost really shouldn't be a surprise for anyone living out in the sticks.