Lily
You seem like a very nice person. Please believe me when I say I know what you are going thru. If you read my posts you will see. I am not criticizing you and I am not "after" you. I really do feel badly for you. You are probably a perfectly fine human being who had no idea what you were getting into when your boyfriend turned out to be an addict.
I promise you that I am just sharing with you some facts that I have learned the hard way, not only from my personal experience, but also from a lot of learning I have done.
*Distinguishing between alcohol and other drugs is a bad idea. Alcohol actually can convert into morphine in the brain. Moreover, regardless of an addict's drug of choice, alcohol can easily lead any addict back to using. Many addicts use alcohol plus another drug. So alcohol is not a "second best" -- it's as bad as using.
*The likelihood of dying from heroin detoxification is very small. It's painful and unpleasant, but it does not lead to death unless the person actually has seizures (which is rare).
*On the other hand, the likelihood of dying from an overdose of heroin is actually pretty high. Heroin is not some kind of government controlled drug. You have no idea what its potency will be until you inject it. And if someone has tried to stay clean for a period of time, their tolerance will be lower, which actually makes the risk of dying higher. Here's an interesting fact: dying from illegal drugs is the most common non-natural form of death in America. And that does not count things like people who commit suicide or are murdered in the course of getting or using drugs.
*You cannot possibly help your boyfriend detox. He needs to be with medical professionals in a controlled, inpatient detox center. I'm sure you love your boyfriend very, very much. But would perform open heart surgery on him at home? I'm guessing not. The only place where he should detox is in a detox facility. If your boyfriend were dangerously ill, you'd take him to the hospital wouldn't you? This is no different.
*There is absolutely nothing you can do to prevent him from taking drugs. Nothing. You can take his clothes away, take his money away, and he will still find a way to do drugs. I once met an addict who made a very revealing point to me. People who have no jobs, no family, no place to live, no formal education and no visible means of support still manage to find a way to use $200 worth of drugs every single day. Drug addicts are the most inventive, resourceful people in the world. You can't stop them.
*Contrary to what you believe, when he is in your home he is NOT in a safe place. He's in a very dangerous place, because he is at continuous risk of using. So he is NOT better off in your home. The only safe place for him right now is a detox center.
*There's only one way to get him to a detox center. Make his life so miserable and uncomfortable that he will be forced to go there. Only when he is in a situation that is utterly untenable will he consider detox. And only then will he be (temporarily) safe.
*In all you are going through, there is a piece of very, very good news that you may have overlooked. Your boyfriend texted you from the stairwell -- hungry, tired, desperate. He reached out to you, not the other way around. At that moment, he was very close to bottom. This means that if he hits bottom again, and you stand your ground, you can force him into detox.
*The logical conclusion, I'm afraid, is very clear. If your boyfriend will not immediately go into detox, you have to kick him out. It's that simple. Tell him he has to go into detox NOW or kick him out IMMEDIATELY. I assure you, there really is no other way.
*Here's the bad news. If you do get him into detox, it is only the very, very beginning in a very long journey. A journey that will take years, and that your boyfriend will most likely fail on at some point. Roughly 80% of heroin addicts relapse (and there are lots of good medical reasons why). So don't look for any magic solution any time soon.
*At some point you may have to decide whether it is worth the pain to stay with him. I cannot tell you what to do. I'm just asking you to keep an open mind about that.
For now, if you really love your boyfriend, and you really want to help him, force him into detox by kicking him out. As many clinicians point out, people forced into detox CAN recover. It does not matter why they go there, it matters why they stay there.