See if he can tell you. It may be appropriate for older children to have a say in planning the consequences. This empowers a child, and he is more likely to follow rules when he had a part in developing them. It's easy to write a list of rules for children who can read, but for the younger one, pictures can work well. A parent can use this technique at home and the child might enjoy it even more it you have photos of him.
Checklists are helpful for everyone, but they are especially important for disorganized children.
Some children don't deal well with change. A new classroom, new teacher, new desk, new classmates can all be upsetting. What looks like odd behavior may simply be a child's inability to adapt to the changes that are required of him. Middle school can be especially difficult as the student is expected to change classes, use a locker, etc. Here is where extra help and lots of patience are in order.