I followed your story with some interest... I am considering taking my daughter to alateen in a year or two, and I expect there to be similar negative repercussions from her dad.
There is no good answer to the problem you face; there's no solution that doesn't have fallout attached to it-- whether it's doing nothing, or getting 100% involved. Please don't feel guilty about the actions you have taken.. there is nothing wrong with anything you've done, you don't sound like you have any ulterior motives. And don't feel guilty if you do decide to clam up. You can legitimately step back under "didn't cause it, can't control it," etc. (I'm surprised that your stepson's mom thinks she is going to get a straight, honest answer out of his dad about how his drinking affects their son. I admire her directness and her assumption that she's going to get the same in return... but her trust is misplaced.)
When this boy becomes an adult, he will look back and judge how his parents, and you, handled this situation. In the long run, his opinion is much more important than what his biological parents think right now. Go easy on yourself
