Well with him being 3 years old, i'm sure he's suposoto be a lot bigger then what he is because of being underfed. Anyways yes, once every 2 months is ignorant, and proves the people had no knowledge of snakes.

So i'm glad you received the rtb. Just make sure he has a constant water source, and since he was underfed, I would say for a while feed him once a week. Other's may recommend once every 2 weeks. The only reason I say once a week is so he can pick up some body size, just make sure the meal is the proper size.