Well he is a damaged and dangerous individual!
Still, I would still go through the motions, and let him know I am watching him, and I mean nothing personally against him personally, but the recidivism rate of ********** doesn't speak favorably on his behalf. I'd encourage him to continues in therapy, because the community at large has a vested interest in his success, but in the event that he is unsuccessful, we are going to work to keep our part of the world as safe as possible. I'd finish with a friendly "I am glad you understand."
I would then make flyers and post them with public information about his crimes as well as a photo. I'd make it very uncomfortable for him to prey in this neighborhood. I'd even go as far as speaking at Scouting events and other ********'s gatherings. So if by some awful chance he victimized anyone, I'd know I've done everything I COULD do to keep kids safe.
Sure some parents would stupidly say "You're scaring our kids, they're confused" but an ounce of prevention is better than a pound of cure. And don't they think their ******** would be "scared, or confused" if *** forbid they were victimized by this person.
Do your part, don't help him keep his secrets. Righteousness is on your side.