He needs to train with Calvin Murphy and learn to shoot free throws. Training with Dream is a waste of time. Training with Shaq would be too because he lacks the size and lower (and upper) body strength Shaq had just like he is missing the speed and agility of Dream. Even if he regains his health, the guy will be completely washed up when he is 32-33 and cannot jump over everyone else in the gym.
i'm not saying he isn't 6'9" without shoes, but remember he was a high schooler at the time, still possible to grow.