Sweetheart, he knows you never meant any of what happened to him. He was a man with his own mind and free will and he did what he wanted, for love of the two of you and your cause. There wasn't anything you could have done to stop him from taking up that cause. He was loyal.
As for your questions, there isn't anything that constitutes who comes here or why. They just do. I don't control who is brought to this world. It's a random process. There's always a chance that he'll show up. I love you dears. Very much. I can feel your love for me, and I know that you pray when you can. Don't beat yourself up over not doing it every day.