That's a terrible story. :( And a timely reminder that 'non-toxic' doesn't mean 'edible'.

It seems like a heartless nitpick but the reason button cells are dangerous is because they're batteries, not because of their constituent chemicals. The electric current they generate electrolyzes water producing highly corrosive hydroxide. A running blender isn't poisonous either, but you wouldn't eat one.

SOME Lithium in your stomach is safe, and in some circumstances is arguably safer than none, as it's an effective, prescribed antidepressant.

But I don't advocate eating batteries. Just saying that Lithium isn't poison in certain quantities.