What is the ruling on dealing with a friend who swore not to speak to me until I swear to him about the veracity of a piece of information, which is in fact untrue, knowing that he only used the oath as a means of pressure?

It appears that the aforementioned oath is binding, and your friend intended to urge you to swear an oath regarding the information, which is the purpose of the oath. So, if he wishes to speak to you, he must offer expiation for breaking an oath, based on the Prophet, peace and blessings be upon him, who said: "By Allah, if Allah wills, I do not swear an oath and then see something else as better than it, except that I expiate for my oath and do that which is better." It is not permissible for you to swear a false oath.