Live in

What can be doen if grandmother doesn't give back grandsons to his father when he wants to settle a new life with his wife. My divorce case is pending and his divorce case is also pending. We both hv filed case from 1.5 yrs back. But now we hv decided to stay together without marrying because divorce is a long process here in India. We decided to stay in LIVE IN till divorce.We took a 2bhk on rent and planning to shift there with both our childre my daughter and his son. But now my live in partner' s mom is dening to give his grandsons to his father and forcing him indirectly to stop taking step for live in. I am 37 and h is 38 yrs old.we suffered a lot due to our bad marriage and saw a dream to settle together and start a new life. Divorce is a lengthy process so can't wait that much. But now my would be husband's mom is preventing him by doing emotional attack by denying to give his son to him and called cops make a statement that i am a bad woman and the child don't want with us. His father is emotionally broken and I am too.plz suggest what can be doen in this condition if any lawyer is reading the case.