Father to get court permission to visit his son..

How to get court permission to visit of son (6 yrs old)..wife not allowing husband to meet his son son?..? my brother filled case against his wife.. they married 2007 ..they have one boy..every thing was fine until 2012..after that she is regularly creating problems and went to her mother house with kid..my brother used to adjust with his wife and ask her to come back...she did it for every month..one time she left..my brother just email & call to come back..she never reply and not attend call..after 6 months she came and ask my mother to leave house and used some bad words..my brother took my mom to relative house in early morning..after that my sis in law family members threatened my brother to give his jewels from bank immediately or huge money..if not they said v will kill him...my brother just came out from home and went back to home city and filled a case on 2013... but still now my brother is not allowing to meet his son by his wife..she is not attending counseliing .. sis in law saying ..she needs money from him to stay with her family members.. its a civil case running for 2 yrs...how my brother get justice to ...his 5 old boy really crying to spend time with dad.. any possible to get custody of child for wekend?