Ok if he built the whole level(without actions) in 3dsmax as one piecepeice, then you can use the Fbx import in Wed to import exactly as it was whole in 3dsmax. However file-> import->fbx will cause Wed to change the models into block. You will the need to replace doors and other things with mapents or models and assign action. Also if you want to use the level as models with lod you will need to break the whole level into parts.
Your kinda asking for all the level work to be drag and drop. It simply isn't that simple. You will still need a level design artist to work with select pieces of a full scene. This is the way all projects work -a to AAA.
Having a full level of assets on hand will allow a designer the ability to focus just on placing the parts together or selected parts if you get a full scene and use a block import.
We have level designers on the forum. (I'll withhold names for now.) That can place together a level for you quickly and ready for you to add actions too. Also some of them maybe able to assign actions as well, as long as you supply the code.