If you're under 6 years old (which perhaps you are?) then yes, your teeth will grow back very soon. Sorry to hear about the car accident. Were your mommy and daddy hurt as well?
Sometimes your permanent teeth are not that permanent. There are cases in history (check the Guiness book of Records) with people that had 4 sets of 'permanent' teeth. But in everyday cases: no... they don't grow back.
If he were 6 years old, he wouldn't have permanent teeth.