Young children who have experienced traumatic fear and shame within their families, may struggle with self-regulation. Regulation can be viewed in terms of arousal levels (fear, calm, and shut down) and in terms of emotional valence (positive vs. negative). Thinking in terms of arousal level and emotional valence together may help parents re-regulate their child.
Links and Reading
Trauma and the Body, by Ogden, Minton, and Pain.
These two books are pretty heavy reading, definitely required reading for therapists. However, many parents will get a lot of these books too.
Hope for Healing, published by ATTACh.org. This is a book written for parents by professionals who are also adoptive parents (including me!) It is a really great place to start and easy to read. I recommend sharing it with grandparents and other family members to help them understand your child.