If he quit or followed through we would have owed it either way.
you incurred this debt that you were going to owe regardless of the outcome. that he bailed on rehab does not change that FACT. of course you had expectations that this expense MIGHT help him on his way.
here's the thing about "helping" or assisting someone else's recovery is that it might not take AT THE TIME.....however (and this goes for members sharing at AA meetings too) the seed MAY have been planted. and that seed MIGHT take 3 months or 3 years to germinate. we just don't know. we are not responsible for the results.
in your last post you were upset that he was not contacting or responding to you. is this you way of getting back at him? trying to throw out a fresh worm on the line and get a bite? we should always check our own motives...........