The demonstratives tips and notes describe these as animate and inanimate, but they don't really get into the details of what that means.

My understanding from reading the dothraki.org wiki is that people will be bony and other demonstratives beginning with b (animate). Animals can have the b words too if the speaker chooses (to regard them as animate).

Most other things - objects and probably plants - I'm guessing are the inanimate k words.

So here it's kony korze issa? Because the sword is neither human nor animal, but instead is inanimate.

But it is bony taoba issa Because the boy is animate.