Everyone that has been touched by a high-control group is impacted, most to a significant degree.
The average therapist has little or no concept of the degree of damage that has been done.
You, your child, and his therapist should all read Bonnie Zieman's book:
http://www.amazon.com/EXiting-JW-Cult-Handbook-Witnesses/dp/1508477132
http://www.exitingthejwcult.com/p/if-you-are-going-to-see-mental-health.html