Aman is Priya's husband. Since Raj is Priya's brother, and Neelam is Raj's wife, Aman and Neelam do not have a direct family relationship, but they are related by marriage. Aman is Raj's brother-in-law because he is married to Raj's sister. By that logic, Neelam is Priya's sister-in-law because she is married to Priya's brother. Aman and Neelam are therefore each other's siblings-in-law or co-siblings-in-law via their respective marriages to Priya and Raj.

Arjun is the son of Priya and Aman, while Kavya is the daughter of Raj and Neelam. Since Raj and Priya are siblings, their children, Arjun and Kavya, are cousins to each other.
Raj is Priya's brother. Priya is married to Aman, and they have a son named Arjun. Raj is married to Neelam, and they have a daughter named Kavya. How are Aman and Neelam related to each other? Also, describe the relationship between Arjun and Kavya.
Respond very briefly.