Self defense is lodged as dowry death case.

My maternal uncle house is near to my home. He has another house in City and he was living there permanently. But he and his second wife (first wife expired due to brain tumor) were not living in village permanently. Even when they married, he didn’t asked anyone, none of the relatives or villagers attended the marriage ceremony although it was second marriage. Some time we came to know that uncle was beaten by aunty. Uncle had two children from first wife, elder son was paralyzed. One day we came to know that elder son got expired, they came to village and after funeral they went back. One day my maternal uncle came to my home with his younger son and started crying. We asked the reason, then he told that his son is being torched by his wife, and he has doubt that his elder son’s death was not natural. He requested us to care his younger son. After listing his pain, we accepted his request. His son was living with us and everything was going normally. Later we came to know that he has bought some land for his wife. Some time later we came to know that he left his home and living here and there. One day he came to village and in night while he was sleeping in his home his wife came and attacked on him with a knife, for self-defense (as maternal uncle is telling) he killed his wife. He called to police just after incident and surrendered. He gave same statement to police. Her brother lodged a FIR against maternal uncle, my mother and two more relatives under IPC 304B, 498A, ¾ Dowry prohibition act. Villagers and neighbors are telling truth to police. After this incident we came to know that his wife had lodged an FIR on maternal uncle, my mother and two more relatives under IPC 498A etc before her death. Sir, my mother is government employ and she is living 150 km away from village, and about 90 KM from City. Other two relatives are also employed in government and private sectors. My mother rarely get time for us. She is being treated as accused only because of caring his son. Charge sheet of main accused is filed and investigation against other accused is continued. On their demand investigating officer is being changed again and again. Sir, please give me some legal advice so that my mother and two other relatives can get relief.