Just keep an eye on him and get a hydrometer.
Sounds like you have regular coco fiber and not husk so you should be fine with that. He can pass the fine fiber if he eats it.
You should try to give him something more natural in plants if you can, even just a single wide leaf bromeliad and snake plant.

Besides the live plant helping in humidity, you will find they love to sleep in or on the bromeliad leafs and snake plant leafs. When adding a plant you need to wash it off well to remove any chance of fertilizer or the introduction of some critter that is dormant in the plant.

I usually remove all the dirt from the root of the plants and replant it right into the coco fiber or attach it to a piece of wood, or insert it into a piece of cork round.

Good luck and keep and eye on your little guy.