To me its the perpetual roller coaster that gets old real quick. When drinking they are impossible. When Sober there is no dissuasion of the drinking phases because hey, they aren't drinking now! Then it is deflected on you, YOU who always has to stir up sh!t when everything is going just fine (aka "I'm not drinking now get off my back. Why do YOU always have to make things awful? Nothing will ever make YOU happy"). The A still driving the boat. Sober for a time, then drinking again. Never really doing anything to support the mental aspect of recovery or long term sobriety. Up down up down up down.
Sounds to me like a good cop bad cop scenario in your home. Dad is going to be the good cop and I don't see that changing. If he can buy a pass its much easier than actually copping to his bad behavior. My parents have always done the same and still do at 80 years old. I loved it when I was younger. As an adult it pisses me off, and I don't want their "gifts" given in exchange of saying "I'm sorry" or "thank you" . I'm happy to say I reached a point years ago where I couldn't be bought. Your kids will get there.
I don't really think you are pissed that he is "sober".