In decipher jumbled up description type of questions, a round-about description is given in the form of certain small relationships and direct relationship between the persons concerned is to be deciphered.
Deepak said to Nitin, "That boy playing with the football is the younger of the two brothers of the daughter of my father's wife."
How is the boy playing football related to Deepak ?
Father's wife -- Mother;
Mother's daughter -- Sister;
Sister's younger brother -- My younger brother.
So, the boy is Deepak's brother.