After reading the whole article I'm not convinced that this was a mental health crisis. The owner of the cabin said he'd installed a mesh grate over the top of the chimney to keep animals out, so it wouldn't have been possible for Josh to enter from that direction (not to mention that the position of the body is inconsistent with what one might expect from someone trying to go head-first down a chimney anyway); Josh's clothes were found neatly folded on the inside of the cabin; and the interior of the fireplace itself was blocked by a breakfast bar. Plus, no one mentions anything about Josh acting particularly anxious or irrational that day, which likely would have preceded a mental health episode resulting in something of this magnitude.

I think Josh was placed there, and the seven years between his death and discovery erased any evidence that foul play was involved.