Is Marriage legal or not

I want legal suggestions for my sister: My sister got married to a guy in arya samaj mandir and got registered by Marriage registrar. After 2 months she realised that the person is fraud and not a good person. Now she ran away from his house after informing police to her parental house. When I gone through the certificates and boys documents I found that it was registered in court on 27 dec. and Marriage was taken place on 26 dec in arya samaj mandir.But my sister was at home on 26th dec. And ran away on 27th dec. for that I have MPR copy ( of 27th dec). When I gone through the documents of boy I found that he has not completed his 21 , he is underage in two documents that is his license and his voter ID. But on adhar card it shows he is 23 years old.Boy doesn't have any other documents as per my sister is saying. Also he had 1 witness of his own and the second witness was arranged by arya samaj advocate. Boy is illiterate and my sister is graduate, she is 28 years old and elder than boy Address which was mentioned in his documents also not true, he was residing on that given address 3-4 years before. I have sent a registered letter on that given address it was return back (on the top of that letter it is written respondent is not in this address). Later my sister told me the boy doesn't reside over there from last 3-4 years. Marriage was solemnized in Gaziabad arya samaj and we belongs to Rajasthan. Please give us legal advice is this marriage nullify.