What is the ruling on distributing questions obtained from a friend after he made me swear not to give them to anyone, knowing that these questions will help students succeed in a difficult subject?

Whoever swears an oath to abandon something and then does it, has broken his oath and must offer expiation for it. Giving the message to non-students after swearing an oath not to give it breaks the oath and necessitates expiation. Giving the memorandum to others after its owner has explicitly forbidden you from doing so is a disclosure of a secret, and it is obligatory to keep it confidential as long as you have committed to that.