If he is addicted, he is sick, (I am a mother, and grandmother, was a sister...) and it is his illness screaming at you---I wish I could say, "Get him into an inpatient treatment center" and think it possible in the system we now do not have...
You would not be doing him or yourself a disservice by getting yourself calm enough to give him a time frame to move out...he may harm himself---he may not, he is obviously terrified of growing up and not having your support, but you cannot let it be okay to be treated badly. The hardest thing is to set the limits, to respond instead of reacting, to not retaliate, yet to not back down. A parent cannot expect gratitude although it may come in time. My concern is, he is sick...I would not give him any money under any circumstances, shelter, food, an ear to hear when he is not abusive, he can "get a job" (or, unfortunately, steal etc) if he wants more...it could be the best thing you do for him is to do as little as possible while maintaining your humanity and acknowledging his.