It definitely can be repaired, how you do it is as much a personal preference as anything. In a pinch, on a workhorse plane that I use for a trainer, I have inserted rods for re-inforcement and just glued everything back together with epoxy because I didn't want to take time to replace the hinges and I wasn't concerned with how ugly it would look. But in your case the rudder and elevator hinges are already removed, so I would take the time to do the repair properly. To do it properly, you do need to remove the portion of the stab that is still glued in the fuse. If this piece or pieces are salvagable after you get them out, then all you need to do is re-postion them, add doublers for strength, and re-cover. If the center portion is not salvagable after getting it removed, you will need to buy a piece of balsa or light plywood the correct thickness and dimensions to cut a replacement piece from.