I have to disagree with Lou. Don't reply at all. When you reply to someone and tell them not to contact you, you're giving out a contradictory message.
Besides, telling him you're "working on your M" is telling him that things are not 100% okay, and THAT is absolutely none of his business. If you reply, you are opening Pandora's Box. If that's what you want... just be aware of it... be conscious.
You don't owe this man anything except your prayers and good wishes, which you can transmit through God.
