(a) Authority.—
A covered official may treat a covered relative of a covered employee under the jurisdiction of that covered official in the same manner the Secretary of a military department treats, under section 481f(d) [1] of title 37, next of kin and family members of a member of the armed forces who dies while located or serving overseas.
(b) Definitions.—In this section:
(3) The term “covered relative” means—
(C)
one or more additional family members of the covered employee, at the discretion of the Secretary a sibling of the covered employee.