Mr. Griffin, please don't take my words for having a hard heart for you or your son, just the oppaset it true, I pray that God's will would be done in your son's life.
If he has the word planted in his soul, he will be OK, this is just a perfecting of his faith, as God did Abraham, so, he and you, will be able to give an account of the hope that lies within you.
Jesus said, he is faithful and true, we go through things this side of heaven, it is all designed to chase us back to God.
Your son can not get to heaven on your faith, he must have his own, which is, in the process of developing right now.
He will have his own testimony of, who God is to him, based on his relationship with his Savior.
I pray for all of our children to know God as there Savior.
Blessing to you my friend