Legal advice please help?

I recently gained guardianship of my niece and nephew through the state and am in the process of trying to adopt. I will give you the short form of the situation so you can understand my question better. As a child i was molested by my brother and my mother never protected me. She told me i couldn’t tell and that this was normal. 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 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. 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 something silly. Any advice is deeply appreciated. Thank you so much in advance.