So my brother is a locksmith at a university and he makes keys and locks for all the doors. He asked to borrow the keys of someone so he could check something. Well apparently those keys opened nearly everything in the school. Including the dorm and it would cost a lot of money to replace the locks for every door in the school if they can't find it.
My brother said he remembers giving the keys back to the person who let him borrow them. So I'd need some advice I can tell him so they don't just gang up on him and put the blame on him.
EDIT: As far as I know there are no cameras where he was so they really can't prove anything