The doctor in the story reported that the water bottle he brought in "had a high concentration of vitamin D," not KCl.

Obviously in this case we are entirely reliant on reporting by one side, and anything in the story could be inaccurate or totally false. But within the context of what's reported, nothing in the story really seems inconsistent with Vitamin D poisoning. And certainly not enough to motivate a weird six-paragraph medical rant like yours.