I didn't know it's poossible to save 2D dwg from the 3D window. Are you sure your consultant has his view set right so he sees everything he's got?
Nevertheless, to make sure, from the 3D view in Archicad, SaveAs 2D lines, then open the saved .2dl file in Archicad.
Now from the plan view, export dwg as usual. this will give the dwg the content you describe.
AC4.1-AC26SWE; MacOS13.5.1; MP5,1+MBP16,1