As opposed to Franz- Joseph, Franz-Ferdinand has stated through a proxy that he favors helping the Pope restore the temporal power. He also favors more autonomy for Serbia-- hardly a reason for 'Serbs' to gun him down.
Pius X and Merry Del Val had procured a concordat with Serbia and this upsets Franz-Joseph-- if the latter was not going to help the Pope regain Papal States then the Pope wasn't going to bend over backwards to help the Emperor.