I understand your frustration. The rehabs ( notice the plural) that my son attended had a bit of a double standard in that while they would not disclose info, they did have expectations of the family if the discussion with the addict revealed plans to return to the home.
It took me a few trips around the block to back off and not participate in the discussions that made me feel obligated.
The real eye-opener was when he spent time in jail, and no one was planning his perfect life upon release. I slept like a baby and spent that time detaching from my feeling of being responsible for his future.
He did not come home to my house afterward. Somewhere in the phone conversations he heard the word "no" and believed it.
So, while all rehabs are different ( one he was in told him to stop calling his mommy, he was an adult with adult problems to take care of ) there are some that will use whatever means possible to show that the addict was deposited safely somewhere, and when they show up back on their doorstep, the family must have enabled. I got very tired of the back off, but pay attention rules.
Just my experience...