Marriage validity

My sister got married in Feb 2016 in aryasamaj temple and got a certificate issued by aryasamaj temple.My brother-in-law is a central government employee in CRPF. He is a divorce and he has no child from his first wife and we all know this and we have seen his divorce paper too but the problem is this that the family of my brother-in-law does not know about his second marriage with my sister and after marriage my brother-in-law treats my sister as a mistress he does not want to reveal his marriage to anybody and also he did not inform his office about his second marriage and whenever my sister or our family ask him to get our sister information update in his office he replies us that aryasamaj marriage certificate is not valid in his department and also he does not get ready to get this marriage registered in court.His behavior is suspicious as the name of his exwife is still registered in his office records and he has a joint account with his exwife too and he also insists my sister to give birth to a child as soon as possible and he will not tell anyone about his marriage with my sister unless my sister does not get pregnant and give birth to a child.kindly tell me is aryasamaj marriage certificate is not valid in central government and how can we get our sister name get registered in our brother-in-law's office on the basis of this aryasamj certificate and what to do exactly to save our sister married life and financial security.