If you showed him support, that will majorly help his recovery and sobriety. When you have someone that supports what you're doing and they love you, it makes the recovery process a lot easier.
He's sober and recovering and doing something that will not only continue to improve his life and mood but it was also help those around him.
The only part I'm not understanding right now is why you're questioning the relationship when he's doing something that's for the better.