Dear Leanne,
I highly recommend that you get a copy of Cece (Freeman) Koester's book "I Am The Child" in which she describes some of the work she did with a child experiencing corticle blindness who improved his vision. Some of the activities are "backing up to move forward" as Cece says. In other words they are previous developmental stage activities to some of the activities in the "Brain Gym" and "Brain Gym(R), Teacher's Edition" books, such as instead of doing Lazy 8s from the Brain Gym books, also described in Cece's book, playing the flashlight game in which you shine a flashlight on the ceiling of a darkened room attempting to get the child to look at it, turn it off and then shine it in another place to get the child to "find it" again. The flashlight game is one of the activities I would recommend for your son.
The Lengthening Activities and Energy Exercises from the Brain Gym books might be appropriate, however Cece describes modifications of those exercises for the more challenged students who are not able to mimic the movements when you do them. Some of the Midline Movements like Cross Crawl may be appropriate for your son, however homolateral crawl and some of the other activities Cece describes may be more appropriate. She describes most of the exercises that are in the Brain Gym books along her modifications for more severely challenged students as well as some of the precursor activities that are more appropriate for more severly challenged students in her book.
The Brain Gym books are targeted more towards normally developed students of first grade age or older who are having mild challenges to learning. We do use some of the activities described in the Brain Gym books with more severly challenged students, though they usually need to be modified from the way they are described in the Brain Gym books, Cece does a good job of this in her book as well as describing other activities that are sometimes more appropriate.
Best Wishes,
Dave Saunders