living with a sibling that is an addict, what would you do?

[29palms]

This could be a long story so I am going to sum it up. My younger brother (23) is an addict. He has been through numerous treatment centers etc. he even lived with myself and my husband for about a year straight and still relapsed, after that I swore he would never live with us again because of the stress it created for me and my husband...About 2 months ago he pulled a knife on my mom and was making threats (due to the drugs) so they called the cops on him and he was arrested.
My mom couldnt stand leaving him in jail and was going to get him out and put him up in a hotel room. (yes a horrible idea) so i suggested that my brother come stay with my husband and myself until he could get into a drug rehab program and would stay only a few days to a week at the most here with us (we live in a nearby state). my brother did go to a 7 day detox center and has been taking his prescriptions (that we pay for, little help from my family) but has been pushing my nerves to the limit.
I have been trying to help him get a job and a truck so he can move on his own but it is proving way harder to deal with him than anticipated. I cannot send him back home to our family's house bc they are not going to allow him back and he would just relapse.
now my husband and I (we have only been married 4 years and half of the time my brother has been staying or living with us) are having to deal with this the best we can.


The last straw was today, my husband and i went on an OVERNIGHT getaway for the holidays and left my brother at our house with specific instructions:
1. no one allowed over
2. if he wanted a mixed drink, he could only have 2 weak drinks before bed.(which is okay with his meds, i checked)
come home this a.m. to find he had not only drank half a bottle of jameson but lied about it saying i was crazy (even though i marked the bottle w a sharpie before w e left)
i was upset but thought maybe I was making a big deal out of nothing so i was checking his email for jobs and saw a facebook message to one of his friends here where we live stating that the friend 'should come over because his sister and brother in law were gone for the night'
i have not confronted him yet and not really sure what to say.. i told him earlier that if he didnt act like a child i wouldnt have to treat him like one which led to an argument.
i am exhausted, frustrated and depressed.. i want to help him but how far do i have to go to make him grow up?
i need ADVICE!!! good advice from serious people.. i am not perfect by any means and there is no handbook given to families of addicts so please guide me i am so lost!!!
my husband and i had been planning this trip for months and i really needed a break for being with my brother 24/7 ..he has no health insurance so everything he does is out of pocket. we could not get him into a longer treatment facility or even a halfway house without $$$ (trust me, i made phone calls for a week straight!) The detox program was the only choice we had at the time now he sees a doc at the health dept but the doc isnt there half the time so not really beneficial. he doesnt have a vehicle to go to A.A. meetings and my husband and i dont have time to run him around..its very disheartening and frustrating!!!