Not as many as you might think. Father Schall passed away a few years ago. He is missed.
He retired in 2012, but is still publishing (this article is from this summer), and from this side of the grave.
Perhaps you are thinking of Cardinal Avery Dulles (son of John Foster Dulles), who had been resident at Fordham. His death, in the words of Father Neuhaus, “set back the Catholic-Jesuit dialogue several decades.”
How did he know about ISIS? Are you sure?