Maybe he's a bad person, but I would prefer if police and justice would handle this in private. If justice is not good enough, then make noise about laws and justice itself so it's changed, but I really dislike this private type of justice. Morally, I see no difference between this and hiring someone to sabotage him financially or physically.
If the problem is here about the PTSD, then I feel like dissociating themselves from the person and getting therapy should be the correct avenues to seek. This feels like the Nirvana baby from the Nevermind cover that had tattoos about the album cover, but was alleging trauma after 30+ years.
And I say this as someone who actually has trauma caused by family members, but in no way I seek public revenge. Sure in private I am the fucking devil, but people have also asked me to participate in dragging their name through the mud and just considering it already makes me feel like shit.