Sorry to hear about your problem, Cam. Take this with a grain of salt because I'm no expert about this sort of thing....I would brick the bottom back in to the way it was initially before the interlocking was installed...BUT!...to do the job right, I'm thinking you may need to remove the threshold of the doorway so that once the brickwork is finished, you can run a couple of beads of caulk on top of the brick to the underside of the threshold and seal the elements out.

Half of communication is listening. You can't listen with your mouth.