Boy christian girl hindu-Case filed under SMOP, NULL and VOID marriage

My friend Marriage happened in church as per Christian marriage law. And the girl left home in few days, saying not interested in marriage life and she asked him to convert to hindu. Boys family realized that Girl is hindu, and they did not told this to boys parents/church. Boy's parents tried to solve this issue by talking to senior community peoples, girl's parents rejected that, and filed a police case of harassment. On enquiry police understands that girls mentality and said to boy deal it in the court. After all this, boy filed a case of NULL and VOID of his marriage. He has both certificates clearly indicated that He is Christian, She is hindu. And the marriage happened as per Christian law, but it should be done by special marriage act as they both are different religious. So boy praying court to announce the marriage is NULL and VOID. Is this case is legally valid? how much time it will take to close this case, since he has all documented proof?