You could try using one of those wall anchors that you use in drywall and put it into the holes to help fill the gap but the best way to do it would be to fill the hole with some thing. I have used toothpicks shoved into the hole to tighten up screws. Adding a little glue helps. You could also use wider screws if they will fit through the holes in the hinge. You could possibly look for a new hinge to replace the existing that has holes in a different spot than the existing hinges so that it would hit all new wood on the door