Question

What roles did members of the black cabinet play in the roosevelt administration that was so sad?

Answer 1

They served as unofficial advisers.

Answer 2

The black cabinet or Federal Council of Negro Affairs or Black Brain Trust was the informal term for a group of African Americans who served as public policy advisors to President Franklin D. Roosevelt and his wife Eleanor Roosevelt in his 1933-45 terms in office.

The roles involved in the members of the black cabinet play was that there was no official  organization. The term was occasionally used in the press.