He should be fine not eating for a day or two.
Frogs/Toads won't eat anything that is not alive and moving, unless "trained" to tong feed. Even then, plant matter is a no-no.

Depending on species, anywhere from 5-20 years. Can you post a picture? If someone here can identify the species, it will be easy to provide you with proper care information. Make sure he has a shallow water dish filled with dechlorinated water, so he can soak if he feels the need.