I agree that you should give this letter to your lawyer. What this man did IS unforgivable!! Drunk driving in combination with a suspended license, that is same as murder attempt to me!!
So, it is great for him that he is trying to change by going to AA; BUT, he has to take consequences too of what he did to you!!

Don't feel as if you HAVE TO answer his letter, if your heart tells you something else. Always follow your heart