1. There are no such thing as dragons (excluding the variety of lizards with "dragon" in their name).
2. He can call whatever he wants a dragon, hell, he can call a dog with a duck beak a dragon if he wants, its his view of dragon, not yours.
3. It has to be physiologically and anatomically correct for it to work in comparison to realism (a sense of it). But if it doesn't that doesn't mean its "retarded".
4. And if he wants to make it a bloody land WALKING dragon from his perspective let him, don't make him use the perspective of others or it will lose what makes it "unique" to HIM.
5. As for the sub names, get over it.
Btw, Chinese and most oriental dragons don't have wings yet fly, go figure that.
Tip: dragons are fantasy beasts and aspects.