Welcome aboard. I agree frogs don't go into brumation at 70 degrees. They make take enviromental cues, like shorter days, and stop feeding. When they do, you need to cool them, because even though their brains say "time to sleep for the winter", their metabolisms are still up and running. By not cooling them, they "digest" themselves, consuming body mass to feed themselves.
But I fear JT may be right.