Have you done the IQ test yet? IQ test does not have math, so I think you can safely test it first.
Is it a school psychologist or is it a private psychologist? Can you delay the achievement appointment to give him a chance to catch up with his math? If you want, you might want to delay both IQ and achievement test appointments if confidence is an issue.
Calm down! I think he can do it but you might need more time than just a few weeks. He has lost his confidence. That will take some time to build it back up.
