My XABF went to inpatient rehab for two and a half weeks. (That's all insurance would pay for; part of that was detox). He was calling me non-stop the entire time, and was so centered on me and telling me what to do and trying to force me to answer his calls that I would be surprised if he got anything out of the experience at all.
The rehab had very strict rules about how often patients were allowed to use the phone (10 minutes a day maximum) and when they could call (the pay phones were turned off the rest of the day). That was nice, except they didn't enforce it - he spent $20 in quarters on the first day there, and kept borrowing the phone at the nurses' station when the pay phones were turned off.
They had all the patients write their New Year's resolutions (he went to rehab on Christmas). The exercise was to write down a list of ten things to stop doing, and ten things to start doing. His were all centered around things that he thought I wanted to hear, and it was obvious that he hadn't really thought about what he wanted to do. They were also the same list. Stop drinking alcohol, stop mistreating StarCat, stop avoiding exercise. Start being sober, start treating StarCat nicely, start exercising. There wasn't anything behind it. To top it off, he showed it to me with his daughter there, and when I pointed out that there was nothing on there about his family and that it was all about me, his response? "I don't understand your question." (His daughter went ballistic - "It wasn't a question! Don't you care about me?!?")
I had split with him by the time he started the outpatient program, and he actually wasn't working at all during the first two weeks, so I can't vouch for it, except to say that at least his family got to experience a mostly-sober XABF because he had to either stop drinking or control his drinking enough to fool the outpatient people, and he had to go about every other day. So I'm guessing they may have appreciated that.
tl;dr
Some inpatient rehabs are better than others, and some alcoholics are better at fooling the system than others. When I visited the rehab people couldn't tell me enough about how well XABF was doing, while I was having a really hard time trying not to strangle him because I had already seen that movie, and I hadn't liked it the first time.