Great news. I am happy for you and your son. How wonderful that he is making you proud. That he is taking some positive steps.
It is a blessing when we get to witness our addicted sons living a productive life. It seems only When they are trying sobriety can we have a relationship with them.
I know the feeling of panic when we don't hear from them for long stretches.
My son stays away when he is active. He told me the worst case for him is to come around and have me see how he is living. I have repeatedly asked him to check in even then so that I know that he is alive, but when he's full-blown addiction mode, he never does. In his case no news is bad news.