autistic and adhd

advice... the school wants me to retain my 6 yr old son in kindergarten sometimes im all for it other times im not. i dont see the point in him repeating the grade again if he is always going to struggle in other grades he has autism and adhd... other times im like yea give him that extra push but i can see now he is always going have problems with learning... i just dont see the point in it... also i dont wont him not graduate and move to 1st with his friends and him wondering why he isnt.. he does an iep though.... others have told me he should move to 1st grade since he has an iep that there is a law or something not sure i live in virginia....