If the wing bone is completely demolished and there is nothing left - not even enough to super glue wires into the hollow ends of the broken bones - then you can make an articulated wire armature to replace the missing bones. Using very sturdy thread, sew it into the cartilage of the wrist joint, using the small loop at the distal end to keep it from slipping around. I like to do it before I wash the birds because it helps to keep the wing feathers in better condition.
Wrap some tape around where the wires overlap (or you can wrap it with thread and superglue with borax. Replace it if necessary after washing.
When it's time to assemble the bird, place some epoxy filler in the area closest to the wrist. You will be able to shape it from the outside in order to smooth the transition area. Wire, wrap and pose the boneless wing as usual, aside from the epoxy reinforcement. (Don't skip that step - it's important.)