How do I determine what damages to ask for in juvenile court after my son was attacked?

My 12 year old son was attacked at school by a student in his class that was making fun of him. About 10 other boys witnessed this and did not go get any help or tell anyone after my son was hurt. He was left alone in a gym locker room all alone hurt for about 10 minutes. He ended up with 2 broken bones in his right arm after the other child threw him on the ground 3 times. He is right handed and could not use his right hand at all for about a week. He had to be put to sleep and have one bone straightened. He missed a week of school. He refused to return to the school that this happened at because he stated he did not feel safe and I had to transfer him to a new school. He had to wear a cast and then a brace for a total of about a month. He had to go weekly for x-rays. He also has to seek mental health therapy after this to help him work through all of his fears and depression resulting from this. His grades in his honors classed suffered dramatically from being forces to miss a week of school and getting behind in his understanding of the material. He has had to drop one of his honors classes because he was unable to catch up to where the class is after missing school and transferring to a new one. We pressed charges and were told that we will be able to request damages for my son. I have no idea how to calculate what would be appropriate to ask for. Any help or recommendations would be greatly appreciated.