Karen,
As stated above, you should start with a medical or psychiatric diagnosis. This will help you with the rationale for why the child needs modifications outside of what is typically afforded children in a general education classroom. It helps to use evidence and research based techniques that support children with significant exposure to adverse childhood experiences. The modifications should be based on his unique needs and provide services that are outside of what a good teacher would provide any student in his/her classroom. Let me know if you have any questions.
Melissa Sadin
Director Creating Trauma Sensitive Schools The Attachment & Trauma Network