Perhaps he has low IQ, perhaps he is somewhere on the
spectrum, perhaps he has add (which is harder to spot than adhd), perhaps he has issues going on at home that make it very hard to do what he needs to do at school (abuse and so forth).
So, your schools team of psychologists, counselor, principal, occupational therapist, intervention specialists, etc. need to now be involved in order to see how this boy may learn the best.
By the way, I'm sure you've gone to his parents.