Call Pathways Caring for Children in Canton or the Adoption Network in cleveland. Or even Children's Hospital in Akron (they have a clinic for adopted kiddos). Double check him to make SURE there is no underlying health issues. They will also be able to give you advice on attachment and sleep issues.
The trick with any child is: Routine, routine, routine. Keep it simple. Here's ours: Pjs and diaper changes, snack, story time with Daddy, brush teeth, sing good night song and kiss all over Mommy then off to bed.
With our 16 month old adopted son, we use a little singing frog that plays classical music for 4 minutes and he likes to watch the ceiling fan.
My other two share a room and we made a tape of ourselves reading stories (Thomas the Tank Engine ad nauseum...). 4 year old plays it in a cassett player; 2 year old listens. They both fall asleep.
Check with the adoption support people before you do too much 'cry it out' time. A little is ok. A lot is dangerous (see Dr. Bryan Post, the Post Institute).