How to deal with certain sexual abuse situation, any input is appreciated?

I recently posted a similar question but would like to hear any further advice also I had other information to include. I gained guardianship of my niece and nephew through the state because my niece was being sexually abused by her father (my brother). As a child i was molested by this same man and my mother never protected me. She told me i couldn’t tell and that this was normal. If I disagreed with her there was physical abuse. My niece and nephew lived with thier father at my mothers house at the time of the abuse. Let me add that the childrens mother is in and out of jail and has abandoned these children. I am now 33 and married with a family of my own. My brother that did this to me has been in and out of jail (not for this) charges were never brought against him on my situation. Now he has a daughter and i found out from my niece that he was doing this to her. I immediately went to the police and a forensic interview was performed. He was indicted on aggravated incest and is in jail awaiting trial. The children were placed in my care, thank god. My mother of course has once again taken his side and is lying to the cops and judges and state etcetera. In the forensic interview it was found out that my mother was allowing my niece to sleep in the bed with her father after my niece told her what was happening, also she was “checking” her bottom my niece says to see if she had been touched. I am trying to push the chance that she may be charged with Passive sexual abuse. I recently found out that a DNA test shows that he is not the biological father to her. Is it possible to keep the charge of aggravated incest because he thought this was his child at the time of the crime? If it was to be dropped what possible charges could we look at that will also carry a lengthy sentence. I also found out that in Louisiana i have 30 years after turning 18 to pursue my charges i only hesitate because his defense is that i coached my niece into lying which i believe will prove differently with the forensic interview. There was no penetration so we only have the interview to go on form the minor which I’m not allowed to hear but have heard from the DA that we have a strong case. I am not sure if it is a good idea to go ahead with my charges because i certainly don’t want him out and able to ever harm anyone else but I fear that they will think i am just trying to target him or get revenge. Usually in these cases that happened so long ago it is hard to prove because there would be no physical evidence, however in my case I have an eye witness willing to testify. If you’re wondering why after all these years? I have suppressed this for so long and when it happened to my niece not only did it bring back the memories of what I went through but I know that there is a pattern and he is never going to stop. I don’t want him to be able to ever harm anyone else again. As far as my mother, there is a restraining order on her for my entire household because of the death threats on me and my children. Any advice is deeply appreciated. Thank you so much in advance.