I strongly disagree with this. It will be better if you make your friend realize that his problem is within and not out there. He needs to take responsibility for his actions, instead of you trying to take a chance with a pious girl’s life. You seem to assume that if he gets married to this girl he will come around and become better. What if the opposite happens and he ends up misguiding her too? You just need to find a different way to support and encourage him to change.