Hi Kristina
My daughter was a lot like this. Her disorganisation caused greater problems the further she progressed through school. The only thing I can suggest that may or may not help, is helping him write and refer to lists. This could also be done in consultation with the teacher and may incorporate putting a special sign or symbol near the door of the classroom, such as a sticker, a blue spot.... so that when he ses it, he has to refer to his list, which may have things such as homework, assignment, hat,....
