Prayers for both of you today.
Just keep praying and ask God to take your son from you right now. Sometimes when I am worried and feeling helpless and unsure of what to do or how to react to my son, or when he is making decisions that will harm him and wouldn't listen to me anyway, I give him to God.
I ask God to take my son and his worries away from me and ask God to walk with him. I picture God walking by my son even as he makes bad decisions then at least I know something GOOD is with him since I can't be.
I understand the worry even as you know there is nothing you can do.:praying