I agree that a person has to have a personal relationship with Christ, but you have to understand that the seed was planted. He accepted Christ even if he didn't understand all the in's and out's.
That takes faith...faith that is a gift from God. I think it is good that he now knows he needs to ask for forgiveness. He should grow in Christ even more now.
Presbyterian parents promise to raise their children as christian to the best of the ability that God gives them. But that doesn't mean the child grows up to understand everything they need to know to become a great example of a christian.
As long as that seed is planted and he is growing in fertile soil, we should see improvement along the way. How fast of improvement...I don't know. I think that has a lot to do with Trump allowing the Holy Spirit to lead him. That's a whole different ball game once a person is saved.