Five Nights at Freddy's - How to pull a Fridge Horror with Scott Cawthon; This weeks episode: Springtrap!

In a series where machines can be possessed by souls, no reason your soul can't posses your own corpse.

For all we know, maybe not all of Ennard escaped his body, and there's just enough machinery to form a skeleton for his soul to inhabit. Which is why he can't die while in the Springtrap suit.