Son can't reach locker at school. School won't allow him to change or share a locker. Looking for tips on how to store and carry his school supplies.

My kids started school last week. The school has top lockers and bottom lockers for the kids to store their supplies. My son has a top locker.The problem is that he isn't tall enough to reach it. He can reach inside bottom of the locker, but can't reach the actual lock. He asked to switch and was told that they do not allow kids to switch lockers. He started sharing with a friend but a teacher noticed and told them that it was against the rules and they would get detention if they continued to share. The kids are also not allowed to wear their backpacks in school, so that isn't an option.What the heck are we supposed to do? He is on the school football team and has a full locker in the gym locker room, but that is on the other side of the school and there is no way he could go there and make it to class on time. Is there something I am missing here? I told him to ask a friend or his sister for help if he sees them in the hall, but with such a limited time to get to class (4 minutes) he is worried that he won't find anyone to help him in time. Asking someone he doesn't know very well means that someone will know his combination. Any tips are much appreciated.Thanks.Edit: My son is 12 and in 7th grade if that makes a difference. via /r/Parenting http://ift.tt/2ivifQj