As you have said your child is taking EPILEX CHRONO200, EPTOIN
Now he is 5 yr old and still not able to speak. So I feel you should perform an IQ assesment. For his other behavioral problem he may need some low dose Risperidon, which will help him severly.
Dont waste time just go for an IQ, he may need some special attention and care. You may consult an PSYCHAITRIST , he will guide you in this matter.