sulted in the funds going to terrorists—was the result of a discretionary function and cannot be the basis for overcoming SHC’s immunity. See U.S. v. S.A. Empresa de Viacao Aerea Rio Grandense WESTLAW (Varig Airlines), 467 U.S. 797, 814, 104 S.Ct. 2755, 81 L.Ed.2d 660 (1984) (explaining FTCA discretionary fun