There are studies that show psychological stress during infancy has been found to cause early impaired memory and a decline in related cognitive abilities. These deficits occur in the hippocampus, a brain region involved in learning, storage and recall of learned memories, thus affecting learning and memory
However, with a family history of learning disabilities as well as his history of trauma, it would be good to have your grand son be evaluated futher by a specialist and a complete neurologic examination be done. This is to ensure that none of his personal history of trauma, visual loss and ear infections could be the causeof his present condition.
Take care and keep us posted.