I think the healthiest text you could send him would be: I need to work on me. You need to work on you and let’s take a break to allow each other to do that. Text me after you’ve been sober for 6 months.
The reality is, if he wants to get sober he’s going to get sober with or without you. What you need to work on is accepting that fact. You do not hold a place in the equation of his sobriety, never have and never will.
If love and support were all alcoholics needed to get sober, there really would be a zillion less alcoholics.