The eye does look cloudy and swollen. Without access to a vet, I would definitely recommend separating the two toads so you can observe the sick toad and keep the hospital setup in pristine conditions. Your tank setup sounds okay, though I would be careful using aquarium gravel. Some of the rocks in the pics look rather small, and I have had toads almost swallow gravel in their enthusiasm to eat. Without a vet at hand and medications, there is not much you can do except try and get your toad to eat and keep everything around it as clean as possible. FBTs are pretty tough and usually pull through minor issues without medical attention. The toad is a good weight, so it just might have the grits to tough this out. Unless someone else has something to offer, I am not sure what more I can tell you. Best of luck and keep me posted.