child molesters

I'm trying to understand something. My family has a past. All do. My dads ex wife molested his two children and had sex with both the daughter and the son. This has probably messed them up and they think that is normal. I can't wrap my head around it all. The son is 30 and still lives with his mom and is very imature. They've never once tried to reach out to my dad. The ex wife must've poisoned them against him. Well I accidentally met the son. He wants to meet my brother and his sister also wants to meet me. They claim they're gunna face my dad. But any one would think they would've years ago when they turned 18. Maybe Sift through the lies on their own. Has anyone here been a victim of molestation? I don't entirely know their perspective. And I hope that they have good intentions when saying they want to meet us.