Since I had already simmed the barb was fairly easy to add this in. And the result....the monk is invincible against the Dragon until they run out of Ki. And you don't even need the patient defense temp HP (so you can save ki there), the monks healing hands were more than enough to compensate for the dragon when it damaged you (which with the deflect attacks, disadvantage on attacks, and high AC, wasn't all the time). It comes down to 3d12 + 7 healing is just more than the dragon ever puts out in one round.
So as long as the monk has Ki (which is 17 rounds if you assume 3 for the superior defense and then 1 ki/round for the flurry), the dragon cannot stop the monk.
UPDATE: Hell I just removed patient defense entirely....its not even needed. Even straight up, you can just get in your two regular attacks, and then heal with flurry attacks as needed, the dragon still can't touch you. Now it can get scary, the dragon did get the monk as low as 11 hp one time, so a player might throw in a patient defense once in a while if they are starting to get really low. But yeah over hundreds of thousands of times never saw the monk die.