drill the back side of the hole if possible, then whoop the drill bit of tap from there.
once its out, drill and tap next size (or two) up and chinese knurl the back side of the tapped hole.
then heat all thread and force it through, all the way with a little hanging out.
hack off the all thread, both ends.
center punch around the all thread, and the edge of the all thread. a lot.
peen the all thread flat.
file flat ( the edge cuts best and planes )
drill and tap the new hole, mo carefully.
most folks can't spot the repair. ;-)