Falling through the cracks

My story starts when my son was about 3. I knew something was off. I kept asking the dr.s. they would reply he is fine. He started school. They put him in the iep program. Was in the special teaching and speech. The add on to his special learning every year. By the time he was in the sixth grade he was in modified classroom. Which made the other kids hateful. Still no one would listen. At 18 he was finally diagnosed with mixed receptive expressive disorder. The dr who did this didn't give him any kind of testing other than talking to him in his office nothing more. This came from a psych dr. Who do I need to take him to?

Susan lowe
Salem, MO