We already have what would probably be the best teacher / mentor for Thabeet on the team. His name is Yao Ming. Let Thabeet work with Yao every day this summer and he will be ready in the fall.
Traditionally speaking, big men need more time to develope then gaurds. The physical tools for Thabeet are there. He just needs to learn to play the game, be in the right places at the right time. He needs to be able to read what the offense is doing and make his rotations. It's more about the mental toughness and knowledge of the game at this point (strictly defensively speaking).
Thabeet should benefit from playing the rest of the season with RGV Vipers and then comes back after the season for serious one-on-one training with the Rockets coaches or Yao, whoever can help him.