boomerang, I think it is unlikely this child has RAD. That generally occurs when an infant is raised in an institutional setting, with multiple caregivers and not enough physical handling and consistent contact with caretakers. Severe attachment disorders generally develop in infancy. They are due to the deprivation of even minimal, consistent social and physical contact with an adult, so, due to a lack of proper nurturing, the child fails to develop any initial primary attachment bond, and this affects all subsequent relationships. These children may also display a failure to thrive.
This Russian child may have had a neglectful or abusive alcoholic mother, but he seems to have had a single primary caregiver in infancy, and probably for the next several years, who likely provided him with at least minimal levels of stimulation and contact. An inconsistent or inadequate or abusive mother may predispose the child to relationship problems, problems in his interactions with others, but that is not the same as true RAD. I think the term RAD has come to be used somewhat loosely these days, to cover a variety of social-behavioral problems which might be due to other causal factors. True RAD is somewhat rare.
At least one passenger on the plane to Moscow, who interacted with this Russian child, described him as behaving and interacting in a fairly normal way for a 7 year old. He was not overly friendly or particularly charming toward strangers, but he was appropriately responsive when the other passenger interacted with him.
I doubt that the child has absolutely no emotional or behavioral problems, as the Russians are asserting. But I also am inclined to doubt that he is as severely disturbed as the adoptive mother has asserted. The truth is likely somewhere in the middle. It is unlikely that he would have emerged completely unscathed from the kind of past treatment he has experienced, and he may lack good coping skills, and he may display emotional and behavioral problems under some conditions more than others. But he is still fairly young, and with proper therapeutic intervention, his problems can be addressed and relearning is possible.
The Russians are not only denying any problems the child might have, they are also suggesting he might have been physically abused by the adoptive mother--they pointed out scars on his body that are of recent origin. Now the child could have injured himself just playing, but I think the Russians are acting defensively, which is what you might expect.
boomerang, experienced child psychologists can use various forms of non-verbal play therapy with children whose language or English use is limited, So treatment is possible even if the therapist isn't fluent in Russian. And the child can speak some English. There may well be someone in that area of Tennessee who can speak Russian, and who can act as a translator for a therapist.