If D has a brother, then how is C related to brother of D?

Answer the questions based on the information given below. Eight persons B, C, D, E, G, H, F and I are in the family of three generations. No single person in the family is a parent. There are only three married couples in the family. C is the only brother of H. B is the brother-in-law of
C. F is the grandson of I, who is sister of G. C is the uncle of F. E is the father-in-law of
D. Gender of G and D is different.